ICRC2015

Europe/Amsterdam
World Forum

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
Description

• Wednesday, July 29
• 4:00 PM 7:00 PM
Registration Onyx

Onyx

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• Thursday, July 30
• 9:00 AM 10:30 AM
Opening, Prizes and Awards World Forum Theater

World Forum Theater

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 9:00 AM
Welcome by the Chair of the ICRC 2015 10m
Speaker: Ad van den Berg (University of Groningen)
• 9:10 AM
Address from the Chair of the IUPAP commission for Astroparticle Physics (C4). 15m
Speaker: Karl-Heinz Kampert (Universität Wuppertal)
• 9:25 AM
Address from the President of the University of Groningen 15m
Speaker: Prof. Sibrand Poppema (University of Groningen)
• 9:40 AM
Prizes and Awards Ceremony 50m
• 10:30 AM 11:00 AM
Coffee & Tea break 30m
• 11:00 AM 12:30 PM
Parallel CR01 Aniso World Forum Theater

World Forum Theater

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 11:00 AM
Anisotropy in Cosmic Ray Arrival Directions Using IceCube and IceTop 15m
We provide an update on the continued observation of anisotropy in the arrival direction distribution of cosmic rays in the southern hemisphere. The IceCube neutrino observatory recorded more than 250 billion events between May 2009 and May 2014. Subtracting dipole and quadrupole fit maps, we can use these increased statistics to see significant small-scale structure that approaches our median angular resolution of 3 degrees. The expanded dataset also allows for a more detailed study of the anisotropy for various cosmic-ray median energies. The large-scale structure observed at median eneries near 20 TeV appears to shift around 150 TeV, with the high-energy skymap showing a strong deficit also present in IceTop maps of similar energies.
Speaker: Stefan Westerhoff (University of Wisconsin-Madison)
• 11:15 AM
Search for High Energy Neutron Point Sources in IceTop 15m
IceTop can detect an astrophysical flux of neutrons from Galactic sources as an excess of cosmic ray air showers arriving from the source direction. Neutrons are undeflected by the Galactic magnetic field and can typically travel 10 ($E$ / PeV) pc before decay. Two searches through the IceTop dataset are performed to look for a statistically significant excess of events with energies above 10 PeV ($10^{16}$ eV) arriving within a small solid angle. The blind search method covers from -90$^{\circ}$ to approximately -50$^{\circ}$ in declination. A targeted search is also performed, looking for significant correlation with candidate sources in different target sets. Flux upper limits can be set in both searches.
Speaker: Michael Sutherland
• 11:30 AM
Full-Sky Analysis of Cosmic-Ray Anisotropy with IceCube and HAWC 15m
During the past two decades, experiments in both the Northern and Southern hemispheres have observed a small but measurable energy-dependent sidereal anisotropy in the arrival direction distribution of galactic cosmic rays. The relative amplitude of the anisotropy is $10^{−4} - 10^{−3}$. However, each of these individual measurements is restricted by limited sky coverage, and so the pseudo-power spectrum of the anisotropy obtained from any one measurement displays a systematic correlation between different multipole modes $C_\ell$. To address this issue, we present the current state of a joint analysis of the anisotropy on all angular scales using cosmic-ray data from the IceCube Neutrino Observatory located at the South Pole (90° S) and the High-Altitude Water Cherenkov (HAWC) Observatory located at Sierra Negra, Mexico (19° N). We present a combined skymap and an all-sky power spectrum in the overlapping energy range of the two experiments at ~10 TeV. We describe the methods used to combine the IceCube and HAWC data, address the individual detector systematics and study the region of overlapping field of view between the two observatories.
Speaker: Juan Carlos Diaz Velez (University of Wisconsin-Madison)
• 11:45 AM
Observation of Anisotropy in the Arrival Direction Distribution of TeV Cosmic Rays With HAWC 15m
The High-Altitude Water Cherenkov (HAWC) Observatory, located 4100 m above sea level near Pico de Orizaba (19° N) in Mexico, is sensitive to gamma rays and cosmic rays at TeV energies. The arrival direction distribution of cosmic rays at these energies shows significant anisotropy on several angular scales, with a relative intensity ranging between $10^{-3}$ and $10^{-4}$. We present the results of a study of cosmic-ray anisotropy based on more than 100 billion cosmic-ray air showers recorded with HAWC since June 2013. The HAWC cosmic-ray sky map, which has a median energy of 2 TeV, exhibits several regions of significantly enhanced cosmic-ray flux. We present the energy dependence of the anisotropy and the cosmic-ray spectrum in the regions of significant excess.
Speaker: Daniel Fiorino
• 12:00 PM
A study of the first harmonic of the large scale anisotropies with the KASCADE-Grande experiment 15m
In this contribution we present the results of a search for large scale anisotropies performed, using the East-West method, with the whole data set of the KASCADE-Grande experiment. The counts distribution in sidereal time intervals of 20 minutes, obtained applying the East-West analysis technique (correctly removing instrumental and atmospheric effects), is analyzed in terms of a dipole component. The amplitude obtained with the whole data set has a 3.5 sigma significance, therefore an upper limit is derived: $A<0.47\times10^{-2}$. To investigate a possible variation of the phase of the first harmonic with energy the search has been repeated in shower size intervals. The errors on the phases obtained in all energy intervals are of the order of 20-30 degrees. The phases obtained point at a sky direction that agrees with those measured at lower energies by the EAS-TOP, IceCube and IceTop experiments and at higher energy by the low energy extension of the Pierre Auger Observatory.
Speaker: Andrea Chiavassa (Universita di Torino)
• 12:15 PM
Measurement of (p+He)-induced anisotropy in cosmic rays with ARGO-YBJ 15m
Deviations from isotropy in the cosmic ray arrival direction distribution indicate the laboratory reference frame moving with respect to the cosmic radiation. When data are ordered in sidereal time, any effect is of great importance, as it may trace potential sources of cosmic rays and probe their propagation through magnetic fields. For the same reason, to decipher results implies unfolding effects from source distribution, energy spectrum and mass composition of cosmic rays, as well as magnetic field on regular and turbulent scales. Any efficient selection of cosmic ray mass would have a major impact on this scenario, as parameters related to cosmic rays production site, acceleration and propagation mechanisms would be importantly constrained in terms of rigidity. So far, no experiment managed to implement efficient mass selections and save high statistics at the same time. The ARGO-YBJ experiment (located at the YangBaJing Cosmic Ray Observatory, Tibet, China, 4300 m asl) is the only detector able to select the cosmic ray light (p+He) component with high efficiency in the wide energy range few TeV - 10 PeV. In this contribution a preliminary measurement of the anisotropy for the p+He primary component is reported for the first time.
Speaker: Roberto Iuppa (Universita e INFN Roma Tor Vergata (IT))
• 11:00 AM 12:30 PM
Parallel CR02 Hadr Int Yangtze 2

Yangtze 2

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 11:00 AM
Status of the LHCf experiment 15m
Observations of UHECRs' by extensive air showers rely on understanding of hadron interactions at very high energies. Recent LHC experiments have provided useful hadron interaction data at the collision energy which is almost equivalent to 10**17 eV in the laboratory frame. Among them, the LHCf experiment is dedicated measurement of neutral particle productions at very forward region of LHC IP1. Two detectors consisting of a pair of compact electromagnetic sampling calorimeters installed at 140 m apart from the IP1, covering the pseudorapidity range eta from 8.6 to infinity. So far measurements of energy spectra for gamma rays, neutral pions, and neutrons have been measured for 7TeV or 0.9 TeV p-p collisions. LHCf has also reported neutral pions from p-Pb collisions at root sNN = 5.02 TeV. Obtained results are compared with the existing cosmic ray interaction models, SYBILL, QGSJETII, DPMJET3, and EPOS. The measured data are well bracketed by these models, although none of them could completely reproduce the data. In 2015 LHCf revisits LHC to obtain p-p collision data at 13 TeV. Current achievement of LHCf experiment and the first look of 13 TeV data as well as future prospects for possible very forward measurement for p-p or p-light ions at RHIC or future LHC will be presented.
Speaker: Yoshitaka Ito (Nagoya University (JP))
• 11:15 AM
The TOTEM experiment at LHC for proton-proton cross section measurements. 15m
The precise knowledge of the proton-proton cross section is extremely important to model the development, in the atmosphere, of the showers induced by the interaction of ultra high energy cosmic rays. The TOTEM (TOTal cross section, Elastic scattering and diffraction dissociation Measurement at the LHC) experiment at LHC, has been designed to measure the total proton-proton cross-section with a luminosity independent method, based on the optical theorem, and study the elastic and diffractive scattering at the LHC energy. This method relies on the capability of the simultaneous measurements of inelastic and elastic rates; in the TOTEM experiment this is possible thanks to two forward inelastic telescopes, covering the pseudorapitidy range 3.1 $< \|\eta\| <$ 6.5, and Roman Pot detectors, that can be inserted down to few hundred microns to the beam centre. Thanks to dedicated runs, taken between 2011 and 2012, with special beam optics, TOTEM experiment was able to measure the elastic, inelastic and total cross-section at $\sqrt{s}=7~TeV$ and $8~TeV$, using the luminosity independent method, along with the pseudorapidity distribution of charged particles. In this contribution the latest results of the TOTEM experiment will be described along with its performance and the future physics program for the LHC run 2.
Speaker: Francesco Cafagna (Universita e INFN, Bari (IT))
• 11:30 AM
Study of high muon multiplicity cosmic ray events with ALICE at the CERN Large Hadron Collider 15m
ALICE is one of four large experiments at the CERN Large Hadron Collider. Located 52 meters underground with 28 meters of overburden rock,it has also been used to detect atmospheric muons produced by cosmic ray interactions in the upper atmosphere. We present the multiplicity distribution of these cosmic ray muon events and their comparison with Monte Carlo simulation. This analysis exploits the large size and excellent tracking capability of the ALICE Time Projection Chamber. A special emphasis is given to the study of high multiplicity events containing more than 100 reconstructed muons and corresponding to a muon areal density larger than 6.7 $m^{−2}$. Similar high muon multiplicity events have been studied in previous underground experiments such as ALEPH and DELPHI at LEP. While these experiments were able to reproduce the measured muon multiplicity distribution with Monte Carlo simulation at low and intermediate multiplicities, they failed to reproduce the frequency of the highest multiplicity events. We demonstrate that the high muon multiplicity events observed in ALICE stem from primary cosmic rays with energies above $10^{16}$ eV. The frequency of these events can be successfully described by assuming a heavy mass composition of primary cosmic rays in this energy range and using the most recent hadronic interaction models to simulate the development of the resulting air showers. This observation narrows the scope alternative, more exotic, production mechanisms for these events.
Speaker: Mario Rodriguez Cahuantzi (Autonomous University of Puebla (BUAP, México)))
• 11:45 AM
Results from pion-carbon interactions measured by NA61/SHINE for better understanding of extensive air showers 15m
The interpretation of extensive air shower measurements, produced by ultra-high energy cosmic rays, relies on the correct modelling of the hadron-air interactions that occur during the shower development. The majority of hadronic particles is produced at equivalent beam energies below the TeV range. NA61/SHINE is a fixed target experiment using secondary beams produced at CERN using the SPS. Hadron-hadron interactions have been recorded at beam momenta between 13 and 350 GeV/c with a wide-acceptance spectrometer. In this talk we present measurements of the identified secondary hadron spectra and the resonance production from pion-carbon interactions, which are essential for modelling air showers.
Speaker: Dr Alexander Edward Herve (Karlsruhe Institute of Technology)
• 12:00 PM
The impact of a fixed-target experiment with LHC beam for astroparticle physics 15m
There are two main points, where the data from a fixed-target experiment with LHC beam will contribute unique information. Firstly, to better understand the inclusive flux of atmospheric neutrinos at very high, PeV, energies. Secondly, to the apparent over-abundance of GeV muons in ultra-high energy extensive air showers. To contribute towards answering these questions, the experimental limitations and requirements for a fixed-target experiment at LHC are presented and discussed. The investigation of forward D-meson production at high-xF is essential in order to distinguish if PeV neutrinos are indeed astrophysical or may also be produced partly within the atmosphere. Furthermore, the production of GeV muons is deeply related to the pion cascade within air showers, and the corresponding pion-air interactions. More precise fixed-target data for pion-Carbon at LHC beam energies will contribute significantly to a better modelling of the muon content of air showers.
Speaker: Dr Ralf Matthias Ulrich (KIT - Karlsruhe Institute of Technology (DE))
• 12:15 PM
Air Shower Development, pion interactions and modified EPOS Model 15m
In detailed air shower simulations, the uncertainty in the prediction of shower observable for different primary particles and energies is currently dominated by differences between hadronic interaction models. With the results of the first run of the LHC, the difference between post-LHC model predictions has been reduced at the same level than experimental uncertainties of cosmic ray experiments. At the same time new type of air shower observable, like the muon production depth, has been measured adding new constraints on hadronic models. Currently no model is able to reproduce consistently all mass composition measurement possible within the Pierre Auger Observatory for instance. Using new modifications in EPOS and LHC data, we will show how air shower measurements can be used to constrain pion-air interactions in kinematic phase space which can not be tested by laboratory experiments. The goal being a model which can reproduce all primary mass composition measurements from air showers in a consistent way.
Speaker: Dr Tanguy Pierog (KIT)
• 11:00 AM 12:30 PM
Parallel GA01 EGAL Yangtze 1

Yangtze 1

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 11:00 AM
Revisiting the starburst galaxy NGC 253 with H.E.S.S. 15m
NGC 253 is one of only two starburst galaxies that is found to emit γ-ray emission from hundreds of MeV to multiple TeV energies. An accurate measurement of the GeV and TeV spectra is crucial to determine the underlying particle accelerators, to probe the dominant emission loss mechanism(s) and to probe the importance of cosmic-ray interaction and transport. The precision of the measurement of the γ-ray emission of the starburst galaxy NGC 253 published in 2012 by H.E.S.S. was dominated by the large associated systematic uncertainties. With the improved understanding of the response of the H.E.S.S. experiment, we present an evaluation of systematic uncertainties of the measurement. We show that they are of the same order of magnitude as the statistical uncertainties. The spectral analysis is discussed for H.E.S.S. separately as well as in combination with the Fermi-LAT measurement. No significant deviation from a single power law is observed. The obtained flux parameters are found to be consistent with the previous measurement within systematic uncertainties. However a ∼ 35 % enhanced flux is now observed. The results of the combined spectral fit strengthen the conclusions presented in Abramowski et al. (2012).
Speaker: Clemens Hoischen (University of Potsdam)
• 11:15 AM
Spectral characteristics of Mrk$\,$501 during the 2012 and 2014 flaring states 15m
The BL$\,$Lac object Mrk$\,$501 was observed at Very High Energies (E$\,$>$\,$100$\,$GeV) with H.E.S.S. (High Energy Stereoscopic System) between 2004 and 2014. The source is detected with high significance above $\sim$2$\,$TeV in $\sim$13.6$\,$h livetime. The observations include periods of low flux and active phases. This led to the detection of strong flaring events, which in 2014 showed a flux level comparable to the 1997 historical maximum. Such high flux states enabled spectral variability and flux variability studies down to a timescale of a few minutes in the 2-20$\,$TeV energy range. During the 2014 flare, the source is clearly detected in each time bin. The spectrum does not show intrinsic curvature in this energy range. Flux dependent spectral analyses are also carried out. The peculiarity of this study resides in the unprecedented combination of short timescales and an energy coverage that extends significantly above 10$\,$TeV. The high energies allow us to probe the effect of EBL absorption at low redshifts, jet physics and LIV. The multiwavelength context of these VHE observations will be presented as well.
Speaker: Mr Gabriele Cologna (LSW Heidelberg)
• 11:30 AM
Discovery of very-high-energy gamma-ray emission from a hard-X-ray bright HBL RX J1136.5+6737 15m
RX J1136.5+6737 (z=0.1342) is a hard X-ray bright high-peaked frequency BL Lac object as listed in the MAXI 3-year catalog as well as the Swift-BAT catalog. The source has also been detected by Fermi-LAT with a hard photon index of $1.68\pm0.12$, and belongs to the first Fermi-LAT catalog of $>10$ GeV sources, showing bright (photon flux = $11.7\times10^{-11}$ ph cm$^{-2}$ s$^{-1}$) emission above 10 GeV. MAGIC observed the source for about 30 hours in 2014 and discovered very-high-energy (VHE) gamma-ray emission from the source with $>5\sigma$ significance. The averaged flux measured by MAGIC during the 2014 observations corresponds to about 1.5% of the Crab Nebula flux at energies above 200 GeV without significant variability. The measured spectrum shows evidence of extending into the TeV energy range, even though most extragalactic background light models predict the distance of z=0.1342 is beyond the "Cosmic gamma-ray horizon" at 1 TeV. Along with the MAGIC observations, we coordinated simultaneous multi-band observations in X-ray and UV bands by Swift, and in optical-IR bands by ground-based telescopes such as Kanata and KVA. In this contribution, the first results of the MAGIC discovery of VHE emission from RX J1136.5+6737 will be reported. We will also discuss origins of the gamma-ray emission with a broad-band spectral energy distribution using our emission model, which takes into account secondary gamma-ray photons produced from cascades induced by ultra-high-energy gamma-ray or protons propagating through intergalactic space.
Speaker: Dr Masaaki Hayashida (Institute for Cosmic-Ray Research, University of Tokyo)
• 11:45 AM
The Denoised, Deconvolved, and Decomposed Fermi gamma-ray sky 15m
We analyze the 6.5 year all-sky data from the Fermi Large Area Telescope restricted to gamma-ray photons with energies between 0.6-307.2 GeV. Raw count maps show a superposition of diffuse and point-like emission structures and are subject to shot noise and instrumental artifacts. Using the D3PO inference algorithm, we model the observed photon counts as the sum of a diffuse and a point-like photon flux, convolved with the instrumental beam and subject to Poissonian shot noise. The D3PO algorithm performs a Bayesian inference in this setting without the use of spatial or spectral templates; i.e., it removes the shot noise, deconvolves the instrumental response, and yields estimates for the two flux components separately. The non-parametric reconstruction uncovers the morphology of the diffuse photon flux up to several hundred GeV. We present an all-sky spectral index map for the diffuse component. We show that the diffuse gamma-ray flux can be described phenomenologically by only two distinct components: a soft component, presumably dominated by hadronic processes, tracing the dense, cold interstellar medium and a hard component, presumably dominated by leptonic interactions, following the hot and dilute medium and outflows such as the Fermi bubbles. A comparison of the soft component with the Galactic dust emission indicates that the dust-to-soft-gamma ratio in the interstellar medium decreases with latitude. The spectrally hard component exists in a thick Galactic disk and tends to flow out of the Galaxy at some locations. Furthermore, we find the angular power spectrum of the diffuse flux to roughly follow a power law with an index of 2.47 on large scales, independent of energy. Our first catalog of source candidates includes 3106 candidates of which we associate 1381 (1897) with known sources from the second (third) Fermi source catalog. We observe gamma-ray emission in the direction of a few galaxy clusters hosting known radio halos.
Speaker: Valentina Vacca (Max Planck for Astrophysics)
• 12:00 PM
Searching for TeV gamma-ray emission associated with IceCube high-energy neutrinos using VERITAS 15m
A potential clue to finding the long-sought-after sources of cosmic rays is the recent observation of an astrophysical flux of high-energy neutrinos by the IceCube detector, since these possibly originate in hadronic interactions near cosmic-ray accelerators. While the neutrino sky map shows no indication of point sources so far, it is possible to utilize the sensitivity of TeV Cherenkov telescopes, such as VERITAS, to search for hadronic gamma-ray emission at the neutrino locations. Over the last 2 years, the positions of neutrino events detected by IceCube have been observed using the VERITAS array. Observations have been limited to muon neutrino events, since their typical angular reconstruction uncertainty is below 1°, smaller than the 3.5° diameter of the VERITAS field of view. The location of VERITAS further constrains the neutrino event positions that can be observed to those located in the northern sky, or at moderate southern declinations. The list of observed positions was selected from published results and a set of high-energy muon tracks provided by IceCube. We present the current status and some preliminary results from this program.
Speaker: Dr Marcos Santander (Barnard College, Columbia University)
• 12:15 PM
AMON Searches for Jointly-Emitting Neutrino + Gamma-Ray Transients 15m
We present the results of archival coincidence analyses between public neutrino data from the 40-string and 59-string configurations of IceCube (IC40 and IC59) with contemporaneous public gamma-ray data from Fermi LAT and Swift. Our analyses have the potential to discover statistically significant coincidences between high-energy neutrinos and gamma-ray signals, and hence, possible jointly-emitting neutrino/gamma-ray transients. This work is an example of more general multimessenger studies that the Astrophysical Multimessenger Observatory Network (AMON) aims to perform. AMON, currently under development at Penn State, will link multiple current and future sensitive high-energy neutrino, cosmic rays and follow-up observatories as well as gravitational wave facilities. This single network enables near real-time coincidence searches for multimessenger astrophysical transients and their electromagnetic counterparts. We will present the component high-energy neutrino and gamma-ray datasets, the statistical approaches that we used, and the results of analyses of the IC40/59+LAT and IC40/59+Swift datasets.
Speaker: Azadeh Keivani (Pennsylvania State University)
• 11:00 AM 12:30 PM
Parallel GA02 GAL Amazon

Amazon

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 11:00 AM
Study of the diffuse gamma ray emission from the Galactic plane with ARGO-YBJ 15m
The data recorded by ARGO-YBJ in more than 5 years have been analyzed todetermine the diffuse gamma ray emission from the Galactic plane. The spatial distribution of the diffuse gamma rays and their energy spectra at Galactic longitudes 25^o < l <100^o o and Galactic latitudes |b|<5^o have been studied. The regions with 40^o< l <100^o and 65^o < l <85^o have been focused, where Milagro observed an excess with respect to the predictions of current models. The energy range investigated covers from ~350 GeV to ~2TeV, connecting the region explored by Fermi-LAT with the multi-TeV energies studied by Milagro. Great care has been taken in masking the TeV point sources observed by ARGO-YBJ and other experiments. Our results are consistent with the predictions of the Fermi model and do not show any excess as observed by Milagro.
Speaker: Dr Lingling Ma (Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences,)
• 11:15 AM
TeV Gamma-Ray Emission Observed from Geminga by HAWC 15m
Geminga is a radio-quiet pulsar ~250 parsecs from Earth that was first discovered as a GeV gamma-ray source and then identified as a pulsar. Milagro observed an extended TeV source spatially consistent with Geminga. HAWC observes a similarly extended source. Observations of Geminga’s flux and extension will be presented.
Speaker: Joshua Wood (University of Maryland, College Park)
• 11:30 AM
TeV Observations of the Galactic Plane with HAWC and Joint Analysis of GeV Data from Fermi 15m
A number of Galactic sources emit GeV-TeV gamma rays that are produced through leptonic and/or hadronic mechanisms. Spectral analysis in this energy range is crucial in order to understand the emission mechanisms. The HAWC Gamma-Ray Observatory, with a large field of view and location at 19º N latitude, is surveying the Galactic Plane from high Galactic longitudes down to near the Galactic Center. Data taken with partially-constructed HAWC array in 2013-2014 exhibit TeV gamma-ray emission along the Galactic Plane. A high-level analysis likelihood framework for HAWC, also presented at this meeting, has been developed concurrently with the Multi-Mission Maximum Likelihood (3ML) architecture to deconvolve the Galactic sources and to perform multi-instrument analysis. It has been tested on early HAWC data and the same method will be applied on HAWC data with the full array. I will present preliminary results on Galactic sources from TeV observations with HAWC and from joint analysis on Fermi and HAWC data in GeV-TeV energy range.
Speaker: Mr Hao Zhou (Michigan Technological University)
• 11:45 AM
RCW 86 - A shell-type supernova remnant in TeV gamma-rays 15m
RCW 86 (also known as G315.4-2.3 or MSH 14-3) is a young supernova remnant about 1800 years old with a shell-like structure in the optical, radio, infrared and X-rays regimes with a diameter of about 40'. We will show detailed morphological and spectral studies of the TeV gamma-ray data measured with the H.E.S.S. telescope system. These studies reveal for the first time a shell-like structure in this energy range that correlates with non-thermal X-rays (2 keV - 5 keV) in the south west region of the remnant. The TeV gamma−ray spectrum is best described by an exponential cutoff power law. Leptonic and hadronic gamma-ray emission scenarios are probed for RCW 86 in a multi-wavelength approach, and the implications of these studies will be discussed.
Speaker: Ira Jung-Richardt
• 12:00 PM
RCW 86 an extended SNR viewed at high energy with the new Fermi-LAT Pass 8 event reconstruction 15m
Supernovae Remnants (SNRs) are thought to be the primary source of galactic cosmic rays observed on Earth. Detected in radio, infrared, X-rays and at high (GeV) and very high energy (TeV) gamma rays, RCW 86 is a good candidate for efficient particle acceleration and might be the remnant of the historical supernova SN 185. Using more than 6 years of data acquired by the Fermi Large Area Telescope with the new Pass 8 event reconstruction, RCW 86 is now detected as a significant extended source at GeV energies, with a radius of 0.37°. The results of our deep morphological and spectral analysis provide new constraints on the origin of the gamma-ray emission and on key parameters such as the asymmetry of the morphology, the density of the surrounding medium and the total energy in accelerated particles. These new constraints will be presented and discussed in the light of existing estimates.
Speaker: Benjamin Condon (CNRS)
• 12:15 PM
Search for new supernova remnant shells in the Galactic plane with H.E.S.S. 15m
Amongst the population of TeV gamma-ray sources detected with the High Energy Stereoscopic System (H.E.S.S.) in the Galactic plane, clearly identified supernova remnant (SNR) shells constitute a small but precious source class. TeV-selected SNRs are prime candidates for efficient cosmic-ray acceleration. In this work, we present new SNR candidates that have been identified in the entire H.E.S.S.-I data of the Galactic plane recorded over the past ten years. Identification with known SNR shells from other wavebands are rare but were successful at least in one case. In a few other cases, TeV-only shell candidates are a major challenge for identification as SNR objects due to their lack of detected non-thermal emission in lower frequency bands. We will discuss how these objects may present an important link between young and evolved SNRs, since their shell emission may be dominated by hadronic processes.
Speaker: Gerd Puehlhofer (IAAT)
• 11:00 AM 12:30 PM
Parallel SH 01 SEP I Mississippi

Mississippi

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands

Solar Energetic Particles

• 11:00 AM
The Longitudinal Distribution of Solar Energetic Particles 15m
Using observations from the High Energy Telescopes on STEREO A and B and similar observations from SoHO, near-Earth, we have identified ~250 individual solar energetic particle events that include >14 MeV protons since the beginning of the STEREO mission (Richardson, et al., Solar Physics, 2014). Between the end of December 2009, when the STEREO A and B spacecraft were, respectively, ahead and behind Earth by ~ 65° in ecliptic longitude, and the end of December 2013, 43 different events were clearly detected at all three locations. The observed intensities of such an event are usually fit with a Gaussian which is a function of the longitudes of the Parker Spiral footpoints at the Sun for each observer. This neglects the fact that the interplanetary magnetic field may have large deviations from Parker Spirals, e.g. due to coronal mass ejections from prior events. Nonetheless, we have fit Gaussians to the peak intensities observed simultaneously at three spacecraft for all 43 events, taking into account particles coming around the Sun both from the east and from the west. The Gaussian peak intensity is poorly correlated with the corresponding CME speed and the FWHM is uncorrelated with the CME speed. Surprisingly, however, there appear to be distinctly non-random variations of the FWHM values from event to event. We will investigate possible causes of this effect.
Speaker: Tycho von Rosenvinge (NASA/Goddard Space Flight Center)
• 11:15 AM
Resolving multiple sources of solar relativistic particles 15m
We perform a comparative study of the time-profile morphology of solar high-energy particle emissions including relativistic electrons in three energy channels of SOHO/EPHIN, relativistic protons as registered by the worldwide network of neutron monitors, and ~100 MeV/n protons and helium in several energy channels of SOHO/ERNE. Based on numerical modeling of the interplanetary transport, we formulate a simple method for resolving the high-energy particle sources operating in solar corona during first hour of the high-energy particle events. The method is applied to Ground Level Enhancement (GLE) and Solar Energetic Particle (SEP) events of the solar cycle 23. We conclude that depending on the GLE-SEP event scenario and detector’s vantage point, the observed particles originate from up to three sources. Possible nature of the sources is discussed in the framework of previous and new models of the high-energy particle production associated with global coronal (EIT) waves and CME bow shocks within five solar radii from the Sun.
Speaker: Prof. Leon Kocharov (University of Oulu, Finland)
• 11:30 AM
SOLAR ENERGETIC PARTICLE EVENTS: TRAJECTORY ANALYSIS AND FLUX RECONSTRUCTION WITH PAMELA 15m
The PAMELA satellite experiment is providing the first direct measurements of Solar Energetic Particles (SEPs) with energies from about 80 MeV to several GeV in near-Earth space, bridging the low energy data from space-based instruments and the Ground Level Enhancement (GLE) data from the worldwide network of neutron monitors. Its unique observational capabilities include the possibility of measuring the flux angular distribution and thus investigating possible anisotropies related to SEP events. This work reports the analysis methods developed to estimate SEP energy spectra as a function of the particle asymptotic pitch angle. The crucial ingredient is provided by an accurate simulation of the asymptotic exposition of the PAMELA apparatus, based on a realistic reconstruction of particle trajectories in the Earth's magnetosphere. Results for the 2006 December 13 and the 2012 May 17 events are presented.
Speaker: Dr Alessandro Bruno (Department of Physics, University of Bari, I-70126 Bari, Italy)
• 11:45 AM
Systematic Behavior of Heavy Ion Spectra in Large Gradual Solar Energetic Particle Events 15m
Our Sun accelerates ions and electrons up to near-relativistic speeds in at least two ways; magnetic reconnection during solar flares is believed to produce the impulsive or $^3$He-rich solar energetic particles (SEPs), while diffusive shock acceleration at fast coronal mass ejection - or CME-driven shock waves are thought to produce the larger gradual SEPs. Despite recent advances in our understanding of the properties (e.g., time variations, spectral behavior, longitudinal distributions, compositional anomalies etc.) of large SEP events, the relative roles played by many important physical processes remain poorly understood. These effects include variations in the seed populations, the geometry and speed of the shock, the presence or absence of a preceding CME from the same active region, scattering by ambient turbulence or by self-generated Alfvén waves during acceleration and transport, and the direct presence of flare accelerated material at energies above $\sim$10 MeV/nucleon. Observations and theoretical studies have indicated that many of these effects may manifest in the spectral properties of H and other heavy elements. In this paper, we present results from a survey of the energy spectra of $\sim$0.1-500 MeV/nucleon H-Fe nuclei in 46, isolated and well-connected large gradual SEP events observed by instruments onboard ACE, GOES, SAMPEX \& SoHO and determine how the spectral fit parameters such as the break or roll-over energies vary with the ion’s Charge-to-Mass (Q/M) ratio. In particular, we compare our results with predictions of existing and developing models to understand why some large SEP events exhibit species-dependent spectral breaks that vary strongly with the ion’s Q/M ratio while others do not.
Speaker: Mihir Desai (SwRI)
• 12:00 PM
A statistical study of 90-MeV proton events observed with SOHO/ERNE 15m
To understand what kind of solar or interplanetary events are capable of producing solar energetic particle (SEP) events with proton energies > 90 MeV, and where and when acceleration of such protons starts. We have selected 40 energetic proton events with intensities > 10−3cm−2 sr−1 s−1 MeV−1 at 93.8–94 MeV, detected by the Energetic and Relativistic Nuclei and Electrons (ERNE) instrument onboard SOHO during solar cycle 23, in 1997–2003. We have estimated the first injection times of the particles using two different methods, the fixed path length method (1.2 AU) and the velocity dispersion analysis. We evaluated the injection time results by comparing each to the estimated height of radio type II/IV burst emission, and then compared the estimated times and heights with related flare and coronal mass ejection (CME) characteristics. Results. We find that all the analysed proton events were associated with CMEs and 82% were associated with on-the-disk GOES X-ray flares (six of the seven non-associated were concluded to show behind-the-limb flaring). Radio type II/IV burst emission association was 95% (of the non-associated two events, one was completely void of radio emission and one showed metric continuum and tilted type III burst lane emission). Most of the first protons were injected when the CME leading edges were below 5 solar radii, and most of the protons reached their maximum intensity while the CMEs were above 10 solar radii. The maximum proton intensities were achieved much earlier than the possible passage of an interplanetary shock, suggesting that the majority of high-energy protons at 90 MeV were accelerated as a result of earlier processes. In roughly half of the events the CME front was above the estimated type II burst location.We suggest that in these cases the type II bursts may be related to CME interaction processes and shocks at the CME flanks.
• 12:15 PM
Unseen GLEs (Ground Level Events) 15m
Over the last seventy years, solar energetic particle (SEP) ground level events (GLEs) have been observed by ground-based neutron monitors and muon telescopes at a rate of slightly more than one per year. Ground-based detectors only measure secondary particles, and matching their observations with SEP in-situ measurements at lower energies from spacecraft has been difficult. Now, the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) instrument provides in-situ measurements that also include composition and pitch-angle distribution and bridge the energy between long-term SEP monitors in space (e.g. ACE and GOES) and the ground-based observations. The PAMELA data show that there are some SEP events (e.g. 23 Jan 2012) where PAMELA sees high-energy (> 1 GeV) particles, yet these are not registered as GLEs. The PAMELA observations indicate that it is possible for the anisotropic distribution of the highest energy SEPs to miss the global network of neutron monitors.
Speaker: Eric Christian (NASA/GSFC)
• 12:30 PM 2:00 PM
Lunch break 1h 30m
• 2:00 PM 3:30 PM
Parallel CR03 Aniso World Forum Theater

World Forum Theater

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 2:00 PM
Large-Scale Distribution of Arrival Directions of Cosmic Rays Detected at the Pierre Auger Observatory and the Telescope Array above $10^{19}$ eV 15m
The large-scale distribution of arrival directions of high-energy cosmic rays is a key observable in attempts to understand their origin. The dipole and quadrupole moments are of special interest in revealing potential anisotropies. An unambiguous measurement of these moments as well as of the full set of spherical harmonic coefficients requires full-sky coverage. This can be achieved by combining data from observatories located in both the northern and southern hemispheres. To this end, a joint analysis using data recorded at the Pierre Auger Observatory and the Telescope Array above $10^{19}$ eV has been performed. For the first time, thanks to the full-sky coverage, the measurement of the dipole moment reported in this study does not rely on any assumption on the underlying flux of cosmic rays. As well, the sensitivity on the quadrupole and higher order moments is the best ever obtained. The resulting multipolar expansion of the flux of cosmic rays allows a comprehensive description of the angular distribution, and in particular to report on the first angular power spectrum of cosmic rays above $10^{19}$ eV.
Speaker: Olivier Deligny (CNRS/IN2P3)
• 2:15 PM
Indications of anisotropy at large angular scales in the arrival directions of cosmic rays detected at the Pierre Auger Observatory 15m
The large-scale distribution of arrival directions of high-energy cosmic rays carries major clues to understand their origin. The Pierre Auger Collaboration has implemented different analyses to search for dipolar and quadrupolar anisotropies in different energy ranges spanning four orders of magnitude. A common phase $\approx 270^\circ$ of the first harmonic modulation in right-ascension was found in adjacent energy intervals below 1 EeV, and another common phase $\approx 100^\circ$ above 4 EeV. A consistency of phase measurements in ordered energy intervals is expected to manifest with a smaller number of events than those needed for the detection of anisotropies with amplitudes standing-out significantly above the background noise. This led us to design a prescribed test aimed at establishing whether this consistency in phases is real at $99\%$ CL. The test required a total independent exposure of 21,000 km$^2$sr yr. Now that this exposure has been reached, we report here the results for the first time. We also report the results of the search for a dipole anisotropy for cosmic rays with energy above 4 EeV including events with zenith angle between $60^\circ$ and $80^\circ$. Compared to previous analyses of events with zenith angles smaller than $60^\circ$, this extension increases by 30$\%$ the size of the data set, and enlarges the fraction of exposed sky from 71$\%$ to 85$\%$. The largest departure from isotropy is found in the energy range above 8 EeV, with an amplitude for the first harmonic in right ascension $r_1^\alpha= (4.4\pm 1.0)\times 10^{-2}$, that has a chance probability $P(\ge r_1^\alpha) = 6.4\times 10^{-5}$, reinforcing the hint previously reported with vertical events alone.
Speaker: Imen Al Samarai
• 2:30 PM
Arrival directions of the highest-energy cosmic rays detected with the Pierre Auger Observatory 15m
We present the results of a search for small scale anisotropies in the distribution of arrival directions of ultra-high energy cosmic rays recorded at the Pierre Auger Observatory. The data set, gathered in ten years of operation, includes arrival directions with zenith angles up to $80^\circ$, and is about three times larger than that used in earlier studies. We update the test based on correlations with active galactic nuclei (AGNs) from the V\'eron-Cetty and V\'eron catalog, which does not yield a significant indication of anisotropy with the present data set. We perform a blind search for localized excess fluxes and for self-clustering of arrival directions at angular scales up to $30^\circ$ and for different energy thresholds between 40 EeV and 80 EeV. We search for correlations with the Galactic Center, the Galactic Plane and the Super-Galactic Plane. We also examine the correlation of arrival directions with relatively nearby galaxies in the 2MRS catalog, AGNs detected by Swift-BAT, a sample of radio galaxies with jets and with the Centaurus A galaxy. None of the searches shows a statistically significant evidence of anisotropy. The two largest departures from isotropy that were found have a post-trial probability $\approx 1.4$\%. One is for cosmic rays with energy above 58 EeV that arrive within $15^\circ$ of the direction toward Centaurus A. The other is for arrival directions within $18^\circ$ of Swift-BAT AGNs closer than 130 Mpc and brighter than $10^{44}$ erg/s, with the same energy threshold.
• 2:45 PM
TA Anisotropy Summary 15m
The Telescope Array has collected 7 years of data and accumulated the largest UHECR data set in the Northern hemisphere. We make use of these data to search for large- and small-scale anisotropy of UHECR. At small angular scales we examine the data for clustering of events and correlations with various classes of putative sources. At large angular scales we will present a blind search for localized excesses of events anywhere on the sky, and find an excess -- the "hot spot" -- at the highest energies by oversampling using a radius of 20 degrees, centered in the constellation Ursa Major. We will estimate the statistical significance of this excess and show how it manifests itself in various other tests. Finally, we will examine the data for correlations with the large-scale structures in the nearby Universe.
Speakers: Hiroyuki Sagawa (RIKEN), Igor Tkachev (Russian Academy of Sciences (RU)), Peter Tinyakov (Universite Libre de Bruxelles (ULB))
• 3:00 PM
Ultra-High-Energy Cosmic-Ray Hotspot Observed with the Telescope Array Surface Detectors 15m
The Telescope Array Experiment has observed a cluster of ultrahigh energy cosmic rays, $E>57$ EeV, called the Hotspot. This was reported in (Abbasi et al., ApJ, 790, L21 (2014)), and was centered in Ursa Major. Using the first five years of data collected by the TA surface detector, the chance probability of this hotspot in an isotropic cosmic-ray sky was calculated to be 3.4$\sigma$. In this work, we update this result using the latest data collected by the TA surface detector. We also discuss possible origins of the hotspot
Speaker: Kazumasa Kawata (ICRR, University of Tokyo)
• 3:15 PM
The Possible Extragalactic Source of Ultra-High-Energy Cosmic Rays at the Telescope Array Hotspot 15m
The Telescope Array (TA) collaboration has reported a hotspot, a cluster of 19 cosmic ray events with energies above $57~\rm EeV$ in a circle of $20^\circ$ radius centered at ${\rm R.A.}(\alpha)=146.^\circ7$, ${\rm Dec.}(\delta)=43.^\circ2$. We explore the hypothesis that the hotspot could originate from a single source. By considering the energy dependent deflections that are expected to affect arrival directions of cosmic rays propagating in cosmic magnetic fields, we identify the nearby starburst galaxy M82 and the bright nearby blazar Mrk 180 as two likely candidates. We discuss prospects of discriminating between the candidate sources with current and future spectral data.
Speaker: Dr Haoning He (UCLA)
• 2:00 PM 3:30 PM
Parallel DM 01 Yangtze 2

Yangtze 2

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 2:00 PM
Recent results and status of the XENON program 15m
The XENON program aims at the direct detection of dark matter WIMPs with liquid xenon as target and detecting material. With detectors of increasing target mass and decreasing background, XENON has achieved competitive limits on WIMP-nucleon interaction couplings, but also on axions and axion-like particles. The XENON100 detector has been ongoing at the Laboratori Nazionali del Gran Sasso in Italy since 2009 with a dual phase xenon Time Projection Chamber employing 161 kg of liquid xenon. The most recent results will be presented. Current run mainly focuses on additional calibration for the low energy response of the detector and the validation of new calibration techniques in view of the next generation experiment, XENON1T. XENON1T will be the first experiment to use liquid xenon in a time projection chamber at the ton scale. It is designed to achieve two orders of magnitude higher sensitivity than the current best limits.
Speaker: Julien Masbou
• 2:15 PM
The XMASS Experimental Program and its Current Implementation 15m
XMASS is an experimental program at the Kamioka Observatory in Japan designed for low energy, low background dark matter searches and neutrino physics. The core technology is a self shielding single-phase liquid xenon detector optimized for maximum scintillation light collection. In this talk we describe its current implementation and discuss its general performance after its 2013 refurbishment.
Speaker: Kai Martens (The University of Tokyo)
• 2:30 PM
Results from the fiducial volume analysis of the XMASS-I dark matter data 15m
XMASS-I, the first phase of the XMASS project, is a direct detection dark matter experiment using 832 kg of liquid xenon. The key idea to reduce the background at low energies in XMASS is to use liquid xenon itself as a shield. In this analysis the clean core of the 832 kg liquid xenon volume is used as sensitive fiducial volume by eliminating the volume near the wall which suffers from beta and gamma rays from the outside. In this talk, we will present the physics results for our direct dark matter search using this fiducial volume of the XMASS-I detector.
Speaker: Atsushi Takeda (University of Tokyo)
• 2:45 PM
The DAMIC dark matter experiment 15m
The DAMIC (Dark Matter in CCDs) experiment uses  high resistivity scientific grade CCDs  to search for dark matter.  The CCD's low electronic noise allows an unprecedently low energy threshold of few tens of eV that makes it possible to detect silicon recoils resulting from interactions of low mass WIMPs. In addition the CCD's high spatial resolution and the excellent energy response results in very effective background identification techniques. The experiment has a unique sensitivity to dark matter particles with masses below 10 GeV. Previous results have demonstrated the potential of this technology, motivating the construction of DAMIC100, a 100 grams silicon target detector currently being installed at SNOLAB. In this presentation, the mode of operation and unique imaging capabilities of the CCDs, and how they may be exploited to characterize and suppress backgrounds will be discussed, as well as the expected physics results after one year of data taking.
Speaker: Joao de Mello Neto (Federal University of Rio de Janeiro)
• 3:00 PM
Search for Dark Matter annihilations in the Sun using the completed IceCube neutrino telescope. 15m
If Dark Matter consists of Weakly Interacting Massive Particles (WIMPs), these might be gravitationally captured in the Sun where they could self-annihilate into standard model particles. Terrestrial neutrino detectors such as IceCube can observe this as an enhanced neutrino flux in the direction of the Sun. Sensitivity has improved with respect to previous searches due to better analysis methods and reconstructions. In addition, improved veto techniques using the outer layers of the cubic kilometre array have been used to reduce the atmospheric muon background and thus improve sensitivity during the Austral Summer. We will present results from an analysis of 341 days of livetime of IceCube-DeepCore in the 86 string configuration.
Speaker: Mohamed Rameez (Universite de Geneve (CH))
• 3:15 PM
The indirect search for dark matter with the ANTARES neutrino telescope 15m
The indirect search for dark matter is a topic of utmost interest in neutrino telescopes. The ANTARES detector is located on the bottom of the Mediterranean Sea 40 km off the southern french coast. ANTARES has been taking data since 2007 when the first half of the detector was installed. In this talk the results of the different analyses for dark matter signals from different potential sources, including the Sun and the Galactic Center, produced with different analysis methods will be presented. The specific advantages of neutrino telescopes in general and of ANTARES in particular will be explained. As an example, the indirect search for Dark Matter towards the Sun performed by neutrino telescopes currently lead to the best sensitivities and limits on the spin dependent WIMP-nucleon cross section with respect to existing direct detection experiments.
Speaker: Christoph Tönnis (Universitat de Valencia)
• 2:00 PM 3:30 PM
Parallel GA 04 Mississippi

Mississippi

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 2:00 PM
Re-examination of the Expected Gamma-Ray Emission of Supernova Remnant SN 1987A 15m
A nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova remnants (SNRs) is employed to re-examine the nonthermal properties of the remnant of SN 1987A for an extended evolutionary period of 5-50 yr. This spherically symmetric model is approximately applied to the different features of the SNR which consist of a Blue Supergiant (BSG) wind and bubble, and the swept-up red Supergiant (RSG) wind structures in the form of an HII region, the "Equatorial Ring" (ER) and the "hourglass" region, all of which are part of a RSG wind whose mass loss rate significantly decreases with elevation above the equatorial plane. The model adapts recent three-dimensional hydrodynamical simulations by Potter et al. (2014). The SNR shock has recently swept up the ER which is the densest region in the immediate circumstellar environment. Therefore the expected gamma-ray energy flux at TeV-energies at the current epoch has already reached its maximal value $\sim 10^{-13}$ erg cm$^{-2}$s$^{-1}$. The general nonthermal strength of the source is expected to decrease roughly by a factor of two over the next 10 yrs.
Speaker: Dr Leonid Ksenofontov (Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy SB RAS)
• 2:15 PM
Search for gamma-ray emission from AGNs with ultra-fast-outflows as candidate cosmic-ray accelerators 15m
Recent X-ray observations of active galactic nuclei (AGNs) have revealed the widespread existence of ultra fast outflows (UFOs), i.e. powerful outflows of baryonic material with velocities $>$10,000 km s$^{-1}$($\sim$0.03 c), seen as variable, blueshifted absorption lines of ionized heavy elements. They have been interpreted as winds driven by the accretion disk, and may be responsible for feedback onto their host galaxies that result in the observed M-sigma relation. In such outflows, various types of shocks are likely to form, either external shocks due to interaction with the ambient medium, or internal shocks due to inhomogeneities within the flow. Such shocks can accelerate electrons and protons to high energies and potentially induce nonthermal emission in various wavebands. In this context, we have searched for gamma-ray emission from AGNs with known UFOs, using Fermi-LAT data $>$100 MeV spanning more than 6 years. The AGN sample of Tombesi et al 2010 is used, with 42 radio-quiet AGNs listed as UFO candidates based on a systematic search for blueshifted Fe K absorption lines. In our current analysis, no significant gamma-ray excess is found from any object in the sample. We compute 95% confidence level gamma-ray upper limits (UL) for all analyzed sources, yielding a mean value for the integrated photon flux ($\geq$100\,MeV) UL of $\sim$3 $\times$ $10^{-9}$ photons cm$^{-2}$ s$^{-1}$, and in the range of $10^{41}$-$10^{45}$ erg s$^{-1}$ for ULs on the gamma-ray luminosity (100 MeV-100 GeV). To assess the properties of this UFO sample, we systematically compared these results with infra-red and radio observations, as well as the estimated kinetic power of the outflow. Our Fermi-LAT upper limits can constrain the ratio of gamma-ray luminosity to outflow kinetic power down to values as low as 0.001. The obtained results impose important constraints on emission models.
Speaker: Ms Yayoi Tomono (Tokai University)
• 2:30 PM
Flat Spectrum Radio Quasars through the MAGIC glasses 15m
The detection of Flat Spectrum Radio Quasars (FSRQs) in the Very High Energy (VHE, E>100 GeV) range is challenging, mainly because of their steep soft spectra in this energy band. Up to now only four FSRQs have been detected in VHE, three of them discovered by MAGIC. The gamma-ray observations observations at such high energies are crucial to understand their emission, especially to constrain the localization of the emitting region within the jet due to the absorption from their broad line region (BLR). Typically, FSRQs are detected during high flux states, enhancing the probability of detection with the current instruments' sensitivities. However, the last observation campaigns performed with the MAGIC telescopes show emission during moderate-quiescent states, thus challenging our understanding of the emission mechanisms in FSRQs. In this contribution, we give an overview and present the most recent results of the three FSRQs 3C279, PKS1222+21 and PKS1510-089 in a multiwavelength context with special focus on MAGIC and Fermi-LAT.
Speaker: Josefa Becerra Gonzalez (NASA GSFC)
• 2:45 PM
Origin of cosmic rays excess in the Galactic Center 15m
The center of our Galaxy hosts a Super-Massive Black Hole (SMBH) of about $4 \times$ 10$^6$ M$_{sun}$. Since it has been argued that the SMBH might accelerate particles up to very high energies, its current and past activity could contribute to the population of Galactic cosmic-rays (CRs). Additionally, the condition in the Galactic Center (GC) are often compared with the one of a starburst system. The high supernovae (SN) rate associated with the strong massive star formation in the region must create a sustained CR injection in the GC via the shocks produced at the time of their explosion. Indeed, the presence of an excess of very high energy (VHE) cosmic rays in the inner 100 pc of the Galaxy has been revealed in 2006 by the H.E.S.S. collaboration. On very large scale ($\approx$ 10 kpc), the non-thermal signature of the escaping GC cosmic rays could have been detected recently as the spectacular "Fermi bubbles". The origin of the CRs over-abundance in the GC still remains mysterious: is it due to a single impulsive or stationary accelerator at the center or to multiple accelerators filling the region? In order to answer these questions, we build a 3D model of CR injection and propagation with a realistic 3D gas distribution. We then compare with existing data (H.E.S.S., Fermi). We discuss the CR injection in the region by a spectral and morphology comparison. We place constrains on the SNR rate and on the diffusion parameters.
Speaker: Mrs Lea Jouvin (APC)
• 3:00 PM
Prospects for Measuring the Positron Excess with the Cherenkov Telescope Array 15m
The excess of positrons in cosmic rays above ∼10 GeV has been a puzzle since it was discovered. Possible interpretations of the excess include acceleration of positron secondaries in local supernova remnants or pulsars, or the annihilation or decay of dark matter particles. To distinguish between these interpretations, the measurement of the positron fraction must be extended to higher energies. One technique to perform this measurement is using the Earth-Moon spectrometer: observing the deflection of positron and electron moon shadows by the Earth’s magnetic field. The measurement has been attempted by previous imaging atmospheric Cherenkov telescopes without success. The Cherenkov Telescope Array (CTA) will have unprecedented sensitivity and background rejection that could make this measurement successful for the first time. In addition, the possibility of using silicon photomultipliers in some of the CTA telescopes could greatly increase the feasibility of making observations near the moon. Estimates of the capabilities of CTA to measure the positron fraction using simulated observations of the moon shadow will be presented.
Speaker: Prof. Justin Vandenbroucke (University of Wisconsin - Madison)
• 3:15 PM
break 15m
• 2:00 PM 3:30 PM
Parallel GA03 Pulsars Amazon

Amazon

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 2:00 PM
Constraining photon dispersion relation from observations of the Vela pulsar with H.E.S.S 15m
Constraining photon dispersion relation from observations of the Vela pulsar with H.E.S.S ------------------------------------------------------------------------ *M.Chrétien, J. Bolmont, A. Jacholkowska, for the H.E.S.S. collaboration* Some approaches to Quantum Gravity (QG) predict a modification of the dispersion relations also known as a Lorentz Invariance Violation. The effect is expected to affect photons near an effective QG energy scale. This value has been constrained by observing gamma rays emitted from variable astrophysical sources such as gamma-ray bursts and flaring active galactic nuclei. Pulsars are periodic transient sources with an extreme variability of ms time scale. In 2014, the H.E.S.S. experiment reported the detection above 30 GeV of gamma rays emitted every 89 ms from the Vela pulsar. Using a likelihood analysis, calibrated with a dedicated Monte-Carlo procedure, we obtain the first limit on QG energy scale with the Vela pulsar. In this talk, the method and calibration procedure in use will be described and the results will be discussed.
Speaker: Mathieu Chrétien (LPNHE CNRS/IN2P3)
• 2:15 PM
A Population of TeV Pulsar Wind Nebulae in the H.E.S.S. Galactic Plane Survey 15m
The H.E.S.S. Galactic Plane Survey (HGPS) constitutes the deepest scan of the inner Milky Way in TeV gamma rays to date. The dominant class of objects in this 10-year survey are Galactic pulsar wind nebulae (PWNe). Aside from a uniform reassessment of the observational parameters of PWNe already found in the past years, the HGPS for the first time allows for the extraction of flux upper limits in regions around pulsars without a detected TeV PWN. Including these limits, we systematically investigate the evolution of quantities such as the TeV luminosity and extension over over $\sim 10^5$ years after the birth of the pulsar. We find that there are trends in their evolution, but also large variations around the average behaviour. This is likely due to the diversity of the surrounding medium and intrinsic starting conditions of the systems. To put the results into context, we present a time-dependent modeling that reproduces both the general trends and the scatter found in the available data of this population.
Speaker: Stefan Klepser (DESY)
• 2:30 PM
Search for gamma rays above 100 TeV from the Crab Nebula using the Tibet air shower array and the 100 m2 muon detector 15m
The Crab Nebula is the standard calibration candle for TeV cosmic gamma-ray experiments. None of those experiments has detected gamma rays above 100 TeV from the Crab Nebula, and the best upper limits have been given by the CASA-MIA experiment. In the circumstances, it is a common understanding that the energy spectrum of the Crab Nebula can be reproduced well by a mechanism based on the synchrotron self-Compton emission of high energy electrons. The observation of the energy spectrum of the Crab Nebula above 100 TeV with high sensitivity is important, in order to confirm the leptonic origin of the TeV gamma-ray emission from the Crab Nebula. To improve the sensitivity of the Tibet air shower array to TeV cosmic gamma rays, we are planning to add an underground 10,000 m$^2$ muon detector array to the existing Tibet air shower array. A small prototype muon detector, 100 m$^2$ in area, was constructed under the Tibet air shower array in the late fall of 2007. In this work, we search for continuous gamma-ray emission from the Crab Nebula above 100 TeV, using the data collected from March 2008 to February 2010 by the Tibet air shower array and the 100 m$^2$ muon detector. We find that our MC simulation is in good agreement with the experimental data. No significant excess is found, and the most stringent upper limit is obtained above 140 TeV.
Speaker: Dr Takashi SAKO (Institute for Cosmic Ray Research, University of Tokyo)
• 2:45 PM
Observations of the Crab Nebula with Early HAWC Data 15m
The High Altitude Water Cherenkov (HAWC) Observatory is a TeV gamma-ray detector which has been completed in early 2015. HAWC started science operations in August 2013 with a fraction of the detector taking data. Several known gamma-ray sources have been already detected with the first HAWC data. Among these sources, the Crab Nebula, the brightest steady gamma-ray source at very high energies in our Galaxy, has been detected with high significance. In this contribution I will present the results of the observations of the Crab Nebula with HAWC, including time variability, and the detector performance based on early data.
Speaker: Francisco Salesa Greus (The Pennsylvania State University)
• 3:00 PM
Six years of VERITAS observations of the Crab Nebula 15m
The Crab Nebula is the brightest source in the very-high-energy (VHE) gamma-ray sky and one of the best studied non-thermal objects. The dominant VHE emission mechanism is believed to be inverse Compton scattering of low energy photons on relativistic electrons. While it is unclear how the electrons are accelerated to energies of 1016 eV, it is general consensus that the ultimate source of energy is the Crab pulsar at the center of the nebula. Studying VHE gamma-ray emission provides valuable insight into the emission mechanisms and ultimately helps to understand the remaining mysteries of the Crab, for example, how the Poynting dominated energy flow is converted into a particle dominated flow of energy. We report on the results of six years of Crab observations with VERITAS comprising 115 hours of data taken between 2007 and 2013. VERITAS is an array of four 12-meter imaging air Cherenkov telescopes located in southern Arizona. We report on the energy spectrum, light curve, and a study of the VHE extension of the Crab Nebula.
Speaker: Dr Kevin Meagher (Université libre de Bruxelles)
• 3:15 PM
The most precise measurements of the Crab nebula inverse Compton spectral component 15m
The Crab pulsar wind nebula (PWN) is one of the best studied astrophysical objects. Due to its brightness at all wavelengths, precise measurements are provided by different kind of instruments, allowing for many discoveries, later seen in other non-thermal sources, and a detailed examination of its physics. Most of the theoretical models for PWN emission are, in fact, based on Crab nebula measurements. The Crab nebula shows a broad-band spectrum spanning from radio frequencies up to VHE gamma rays and consists of two components, one of synchrotron origin and the other one due to radiative inverse Compton losses, starting at a few GeV. We will report the most precise measurements of the inverse Compton component from the Crab Nebula by combining data by the LAT detector on board of the Fermi satellite (1-300 GeV) and by the stereoscopic MAGIC system (>50 GeV). At low energies, the MAGIC results, combined with the Fermi/LAT data, show a flat and broad inverse Compton peak. The overall fit to the data between 1 GeV and 30 TeV is well-described by a modified log-parabola function with an exponent of 2.5, and places the position of the inverse Compton peak at around 53 GeV. The spectral measurements obtained by the MAGIC collaboration cover more than three decades in energy, allowing to address the still-open question about the maximum energy reached by the parent electron population. The broadness of the inverse Compton peak cannot be reproduced by either the constant B-field model or the MHD flow model. The conclusion, based on earlier data, that simple models (constant B-field, spherical symmetry) can account for the observed spectral shape has to revisited at the light of the new MAGIC results. On the other hand, the time-dependent 1D spectral model provides a good fit of the new VHE results when considering a 80uG magnetic field. However, it fails to match the data when including the morphology of the nebula at lower wavelengths.
Speaker: Roberta Zanin (Universitat de Barcelona)
• 2:00 PM 3:30 PM
Parallel NU 01 Yangtze 1

Yangtze 1

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 2:00 PM
Photon-neutrino flux correlations from hadronic models of AGN? 15m
Neutrino production in jetted AGN is linked to hadronic processes such as photomeson production. The same interaction predicts also high-energy photons, mostly via neutral pion decay. While neutrinos escape the source unattenuated, the hadronically produced high-energy photons and pairs initiate pair cascades in most cases which re-distribute their energy to lower frequencies where photons can escape the emission region. Realistic hadronic emission models of AGN jets take into account competing energy losses of injected/accelerated particles as well as all leptonic processes (owing to primary and secondary electrons). This may smear out any intrinsic correlation between emerging photon and neutrino fluxes. The goal of this work is to investigate the degree of observable photon-neutrino flux correlations that is expected from hadronic AGN jet emission models. For this purpose the expected neutrino spectra from a number of hadronically modeled broadband spectral energy distributions (SEDs) of powerful blazars is calculated and compared to the photon fluxes at various frequencies by means of a correlation analysis. The results have implications for the search of the photon sources that are associated to the TeV-PeV neutrino events reported by neutrino observatories.
Speaker: Anita Reimer (University of Innsbruck)
• 2:15 PM
Neutrinos from Clusters of Galaxies and Radio Constraints 15m
Cosmic-ray (CR) protons can accumulate for cosmological times in clusters of galaxies. Their hadronic interactions with protons of the intra-cluster medium (ICM) generate secondary electrons, gamma-rays and neutrinos. In light of the high-energy neutrino events recently discovered by the IceCube observatory, we estimate the contribution from galaxy clusters to the diffuse gamma-ray and neutrino backgrounds. For the first time, we consistently take into account the synchrotron emission generated by secondary electrons and require the clusters radio counts to be respected. For a choice of parameters respecting current constraints from radio to gamma-rays, and assuming a proton spectral index of -2, we find that hadronic interactions in clusters contribute by less than 10% to the IceCube flux, and much less to the total extragalactic gamma-ray background observed by Fermi. They account for less than 1% for spectral indexes <-2. The high-energy neutrino flux observed by IceCube can be reproduced without violating radio constraints only if a very hard (and speculative) spectral index >-2 is adopted. However, this scenario is in tension with the high-energy IceCube data, which seem to suggest a spectral energy distribution of the neutrino flux that decreases with the particle energy. We stress that our results are valid for all kind of sources injecting CR protons into the ICM, and that, while IceCube can to test the most optimistic scenarios for spectral indexes $\ge$-2.2 by stacking few nearby massive galaxy clusters, they cannot give any relevant contribution to the extragalactic gamma-ray and neutrino backgrounds in any realistic scenario.
Speaker: Fabio Zandanel (University of Amsterdam)
• 2:30 PM
Neutrinos and the origin of the cosmic rays 15m
We discuss the interplay between the high-energy neutrino flux observed by IceCube and cosmic ray observations. One question is if the neutrino flux can be reconciled with the paradigm that it comes from the sources of the UHECRs. Another one is how many of these neutrinos can stem from cosmic ray interactions with hydrogen in the Milky Way if the chemical composition of the cosmic rays is taken into account.
Speaker: Walter Winter (DESY)
• 2:45 PM
On the neutrino emission from BL Lacs 15m
The recent IceCube discovery of 0.1-1 PeV neutrinos of astrophysical origin opens up a new era for high-energy astrophysics. There are various astrophysical candidate sources, including active galactic nuclei (AGN) and starburst galaxies. Yet, a firm association of the detected neutrinos with one (or more) of them is still lacking. This talk will focus on the possible association of IceCube neutrinos with BL Lacs, a sub-class of radio loud AGN. We present the results from leptohadronic modeling of six individual BL Lacs, including the closest to Earth, Mrk 421, that were selected as probable counterparts of the IceCube neutrinos. We also show the cumulative neutrino emission from BL Lacs, which was calculated by incorporating our results from the modeling of individual sources to Monte Carlo simulations for the blazar evolution. We finally discuss our results in the light of current IceCube limits (above 2 PeV) and a possible future detection.
Speaker: Dr Maria Petropoulou (Purdue University)
• 3:00 PM
Detectability of GRB blast wave neutrinos in IceCube 15m
Accelerated ultrahigh-energy cosmic rays (UHECRs) in long-lived gamma-ray burst (GRB) blast waves are expected to interact with X-ray to optical-infrared photons of GRB afterglow to produce PeV-EeV neutrinos. These long-lived neutrino fluxes can last for a time scale of days to years, in contrast to the prompt neutrino fluxes under the internal shocks model with a time scale of seconds to minutes and which has been constraint by recent IceCube GRB search. We calculate the expected neutrino events in IceCube in the PeV–EeV range from the blast wave of long-duration GRBs, both for individual nearby GRBs and for the diffuse flux. We show that EeV neutrinos from the blast wave of an individual GRB can be detected with long-term monitoring by a future high-energy extension of IceCube for redshift up to z ∼ 0.5. We also show that with 5 years operation IceCube will be able to detect the diffuse GRB blastwave neutrino flux and distinguish it from the cosmogenic GZK neutrino flux if the UHECRs are heavy nuclei.
Speaker: Dr Lili Yang (University of Nova Gorica)
• 3:15 PM
A HADRONIC SCENARIO FOR THE GALACTIC RIDGE EMISSION 15m
During the last decade the innermost part of our galaxy has been observed as a gamma-ray emitting region described by a ridge-like surface. In particular, in 2005 the H.E.S.S. collaboration reported the measurement of a power-law spectrum with index close to -2.3, between 0.1 and 10 TeV, strongly correlated with dense molecular clouds in that region. Last year the VERITAS collaboration confirmed that finding. Below that energy a diffuse non-thermal emission was also found by the Fermi-LAT observatory with a spectrum, related to this region, which can be smoothly connected to that measured by H.E.S.S.  Although several hypotheses have been proposed for the origin of that emission - e.g.  flaring activity of the SgrA* supermassive black hole as well as steady leptonic and hadronic emission from freshly accelerated cosmic rays  (CR) - it was recently shown as those results can be consistently interpreted in terms of hadronic emission produced by the Galactic CR population in the presence of radial dependent transport.  Since the Galactic CR spectrum extends at least up to several PeVs, a very high energy neutrino emission is expected from the considered Galactic Center region which should exceed the atmospheric background for a kilometric scale neutrino telescope.  Here, we adopt such scenario to estimate the expected signal in the IceCube observatory and compare it with its recent results. Moreover, we will discuss the detecting chances of neutrino telescopes in the North hemisphere, as  ANTARES and the future KM3NeT, which are better positioned for the observation of the Galactic Ridge.
Speaker: Dr Antonio Marinelli (Physics Institute, Pisa University)
• 3:30 PM 4:30 PM
Poster 1
• 3:30 PM 4:30 PM
Poster 1 CR Amazon Foyer

Amazon Foyer

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 3:30 PM
A branching model for hadronic air showers 1h
We introduce a simple branching model for the development of hadronic showers in the Earth's atmosphere. Based on this model, we show how the size of the pionic component followed by muons can be estimated. Several aspects of the subsequent muonic component are also discussed. We focus on the energy evolution of the muon production depth. We also estimate the impact of the primary particle mass on the size of the hadronic component. Even though a precise calculation of the development of air showers must be left to complex Monte Carlo simulations, the proposed model can reveal qualitative insight into the air shower physics.
Speaker: Vladimir Novotny (Charles University in Prague)
• 3:30 PM
A Look at the Cosmic Ray Anisotropy with the Nonlocal Relativistic Transport Approach 1h
Cosmic Ray anisotropy is a key element in the quest to ﬁnd the origin of the enigmatic particles. A well known problem is that although most of the likely sources are in the Inner Galaxy, the direction from which the lowest energy particles (less than about 1 PeV) come is largely from the Outer Galaxy. We show that this can be understood taking into account a possible reﬂection of charged particles by some 'walls' in the Interstellar Medium. This effect is too subtle to be explained by an ordinary diffusion theory and becomes apparent within the frames of the nonlocal relativistic transport theory, which involves conceptions of free motion velocity and path lengths with probability distribution of nonexponential type taken for a turbulent interstellar medium.
Speaker: Dr Renat Sibatov (Ulyanovsk State University, Ulyanovsk, Russia)
• 3:30 PM
A method for reconstructing the muon lateral distribution with an array of segmented counters with time resolution 1h
Although the nature of ultra high energy cosmic rays is still largely unknown, significant progress has been achieved in last decades with the construction of the large arrays that are currently taking data. One of the most important pieces of information comes from the chemical composition of primary particles. It is well known that the muon content of air showers generated by the interaction of cosmic rays with the atmosphere is rather sensitive to primary mass. Therefore, the measurement of the number of muons at ground level is an essential ingredient to infer the cosmic ray mass composition. The energy range from $3 \times 10^{17}$ eV to $10^{20}$ eV is considered using two triangular arrays spaced at 750 m and 1500 m respectively. We introduce here a novel method for reconstructing the muon lateral distribution function with an array of segmented counters. The reconstruction builds on a previous method we recently presented by considering the time resolution of the detectors. We show that the new method improves the statistical uncertainty of the measured number of muons with respect to the previous alternative. The new reconstruction has also the additional advantage of estimating uncertainties in the number of muons without bias. These improvements make a difference in composition analyses. While the increased resolution allows for a better separation between different primary masses, correct uncertainties are required for a meaningful classification of cosmic rays on an event-by-event basis.
Speaker: Brian Wundheiler (Instituto de Tecnologias en Deteccion y Astroparticulas)
• 3:30 PM
A new version of the event generator Sibyll 1h
The event generator Sibyll can be used for the simulation of hadronic multiparticle production up to the highest cosmic ray energies. It is optimized for providing an economic description of those aspects of the expected hadronic final states that are needed for the calculation of air showers and atmospheric lepton fluxes. New measurements from fixed target and collider experiments, in particular those at LHC, allow us to test the predictive power of the model version 2.1, which was released more than 10 years ago, and also to identify shortcomings. Based on a detailed comparison of the model predictions with the new data we revisit model assumptions and approximations to obtain an improved version of the interaction model. In addition a phenomenological model for the production of charm particles is implemented as needed for the calculation of prompt lepton fluxes in the energy range of the astrophysical neutrinos recently discovered by IceCube. After giving an overview of the new ideas implemented in Sibyll and discussing how they lead to an improved description of accelerator data, predictions for air showers and atmospheric lepton fluxes are presented.
Speaker: Ralph Richard Engel (KIT - Karlsruhe Institute of Technology (DE))
• 3:30 PM
A Novel CubeSat-Sized Antiproton Detector for Space Applications 1h
Measuring cosmic antimatter fluxes probes many astrophysical processes. The abundancies and energy spectra of antiparticles support the understanding of the creation and propagation mechanisms of cosmic rays in the Universe. Deviations from theoretical predictions may hint to exotic sources of antimatter or inaccuracies in our understanding of the involved processes. Specifically, geomagnetically trapped antiprotons in Earth's inner radiation belt are directly linked to the production of secondary cosmic ray particles and their motion in Earth's magnetic field. The planned Antiproton Flux in Space (AFIS) experiment is designed to measure this antiproton flux using a novel CubeSat-sized particle detector. This active-target detector consists of 900 scintillating fibers read out by silicon photomultipliers and is sensitive to antiprotons in the energy range below 100 MeV. With its almost 4π angular acceptance, it covers a geometrical acceptance of 270 cm²$\cdot$ sr. The particle identification scheme for antiprotons relies on a combination of Bragg curve spectroscopy and the characteristics of the annihilation process. In order to verify the detection principle, a prototype detector with a reduced number of channels was tested at a stationary proton beam. Its energy resolution was found to be less than 1 MeV for stopping protons of about 50 MeV energy. We will give an overview of the AFIS mission and explain the working principle of the detector. We will also discuss the results from the beam test and the construction of the first full-scale detector. This research was supported by the DFG cluster of excellence “Origin and Structure of the Universe” (www.universe-cluster.de).
Speaker: Mr Thomas Pöschl (Technische Universität München)
• 3:30 PM
An IceTop Module for the IceCube MasterClass 1h
The IceCube MasterClass is an outreach project of the IceCube experiment at South Pole for 9th to 12th grade school students. The MasterClass is designed to provide an authentic astrophysics research experience by demonstrating typical elements of IceCube research. It is a full-day experience of engaging activites, eductional talks, and scripted analyses, where students can reproduce the main science results of IceCube with real data. Interactive applications are a central aspect of the analysis activities, which run directly in standard web browsers and offer students intuitive insights into data processing. This contribution describes a new analysis module which reproduces the measurement of the energy spectrum of cosmic rays with IceTop, the surface component of IceCube. The module features a web application that allows students to interactively fit representative IceTop events to recover the direction and size estimator S125 from the raw data. Data from the web application is processed with a simple spreadsheet application to compute the cosmic-ray flux, which can be compared to the official result.
Speaker: Dr Hans Peter Dembinski (Bartol Institute, Dept of Physics and Astronomy, University of Delaware)
• 3:30 PM
Anisotropy search in the Ultra High Energy Cosmic Ray Spectrum in the Northern Hemisphere using the Telescope Array surface detector 1h
The Telescope Array (TA) experiment is located in the western desert of Utah, USA and observes ultra high energy cosmic rays in the northern hemisphere. In the highest part of the energy region, the cosmic ray energy spectrum shape carries information of the source density distribution. We search for directional differences in the energy spectrum shape. In this study, observed cosmic ray energy distributions are compared between sky areas that contain nearby objects, such as the super-galactic plane, and others that do not.
Speaker: Dr Toshiyuki Nonaka (Institute for Cosmic Ray Research, University of Tokyo)
• 3:30 PM
Astrophysical expectations for the variation of the UHECR composition across the sky 1h
Using an integrated propagation code that takes into account particle energy losses, nuclear photo-dissociation and deflections by Galactic and extragalactic magnetic fields, we simulate representative sky maps of ultra-high-energy cosmic rays over the entire sky, for a wide range of astrophysical scenarios, with different source density, spectrum and composition. We analyze these sky maps from the point of view of composition variations in different regions of the sky, and present a statistical analysis of the significance of such variations. In particular, we apply the study to the typical differences that might be expected between the northern and southern hemispheres.
Speaker: Simon Bacholle (APC- Paris Diderot university)
• 3:30 PM
Atmospheric monitoring at the Pierre Auger Observatory using the upgraded Central Laser Facility 1h
The Fluorescence Detector (FD) at the Pierre Auger Observatory measures the intensity of the scattered light from laser tracks generated by the Central Laser Facility (CLF) and the eXtreme Laser Facility (XLF) to monitor and estimate the aerosol optical depth (tau(z,t)). These measurements are important to have unbiased and reliable FD reconstruction of the energy of the primary cosmic ray, and the depth of the maximum shower development. In 2013 the CLF was upgraded substantially with the addition of a solid state laser, new generation GPS, a robotic beam calibration system, better thermal and dust isolation, and improved software. The upgrade also includes a back-scatter Raman LIDAR receiver, capable of providing independent measurements of tau(z,t). We describe the new features and applications of the upgraded instrument, including an automated energy calibration system, a steered firing system used for arrival direction studies, and the atmospheric monitoring measurements. We also present the first results after the upgrade using three different procedures to calculate tau(z,t). The first procedure compares the FD hourly response to the scattered light from the CLF (or XLF) against a reference hourly profile measured during an extremely clear night where zero aerosol contents are assumed. The second procedure measures tau(z,t) by comparing simulated FD responses under different aerosol attenuation parameters and selecting the best fit to the actual FD response. The third procedure uses the new Raman LIDAR receiver in-situ to measure the back-scattered light from the CLF laser. The comparison shows a good agreement for the first and second procedures for all FDs located at similar distances from the facilities. However we found higher values of tau(z,t) using the Raman measurements. This difference may indicate that the assumption of a zero aerosol content during the reference night selection may not be accurate.
Speaker: carlos medina-hernandez (colorado school of mines)
• 3:30 PM
AugerNext: R&D studies at the Pierre Auger Observatory for a next generation ground-based ultra-high energy cosmic ray experiment 1h
The findings so far of the Pierre Auger Observatory and those of the Telescope Array define some requirements for a possible next generation global cosmic ray observatory: it needs to be considerably increased in size, it needs good sensitivity to composition, and it has to cover the full sky. At the Pierre Auger Observatory, AugerNext aims to conduct some innovative initial research studies on a design of a sophisticated hybrid detector fulfilling these demands. Within a European supported ASPERA/APPEC (Astroparticle Physics European Consortium) project for the years 2011-2014, such R&D studies primarily focused on the following areas: i) consolidation of the detection of cosmic rays using MHz radio antennas; ii) proof-of-principle of cosmic ray microwave detection; iii) test of the large-scale application of new generation photo-sensors; iv) generalization of data communication techniques; and v) development of new schemes for muon detection with surface arrays. This contribution summarizes the achievements of these R&D studies within the AugerNext project.
Speaker: Andreas Haungs (Karlsruhe Institute of Technology)
• 3:30 PM
Automated procedures for the Fluorescence Detector calibration at the Pierre Auger Observatory 1h
The quality of the physics results, derived from the analysis of the data collected at the Pierre Auger Observatory depends heavily on the calibration and monitoring of the components of the detectors. It is crucial to maintain a database containing complete information on the absolute calibration of all photomultipliers and their time evolution. The low rate of the physics events implies that the analysis will have to be made over a long period of operation. This requirement imposes a very organized and reliable data storage and data management strategy, in order to guarantee correct data preservation and high data quality. The Fluorescence Detector (FD) consists of 27 telescopes with about 12,000 phototubes which have to be calibrated periodically. A special absolute calibration system is used. It is based on a calibrated light source with a diffusive screen, uniformly illuminating photomultipliers of the camera. This absolute calibration is performed every few years, as its use is not compatible with the operation of the detector. To monitor the stability and the time-behavior, another light source system operates every night of data taking. This relative calibration procedure yields more than $2{\times}10^4$ raw files each year, about 1 TByte/year. In this paper we describe a new web-interfaced database architecture to manage, store, produce and analyze FD calibration data. It contains the configuration and operating parameters of the detectors at each instant and other relevant functional parameters that are needed for the analysis or to monitor possible instabilities, used for the early discovery of malfunctioning components. Based on over 10 years of operation, we present results on the long term performance of FD and its dependence on environmental variables. We also report on a check of the absolute calibration values by analyzing the signals left by stars traversing the FD field of view.
Speaker: Gaetano Salina (Istituto Nazionale di Fisica Nucleare)
• 3:30 PM
Azimuthal asymmetry in the Cherenkov radiation of EAS 1h
For the study of Extensive Atmospheric Showers (EAS) is essential the reconstruction method of Cherenkov radiation produced by charged secondary particles. In the recent studies it was shown that to greater accuracy of the reconstruction parameters of the EAS appears as a dependence of the spatial distribution of Cherenkov radiation as function of the azimuth angle, this due to the influence of the geomagnetic field Earth's. The calculation of this dependence, in principle, could improve the accuracy of the determination of the characteristics of the primary particles based on the Cherenkov measurements. In this work, a study is presented to find the azimuth dependence of the data Tunka's.
Speaker: Mr Jorge Cotzomi (FCFM BUAP)
• 3:30 PM
CALET measurements with cosmic nuclei: expected performances of tracking and charge identification 1h
CALET is a space mission currently in the final phase of preparation for a launch to the International Space Station (ISS), where it will be installed on the Exposed Facility of the Japanese Experiment Module (JEM-EF). In addition to high precision measurements of the electron spectrum, CALET will also perform long exposure observations of cosmic nuclei from proton to iron and will detect trans-iron elements with a dynamic range up to Z=40. The energy measurement relies on two calorimeter systems: a fine grained imaging calorimeter (IMC) followed by a total absorption calorimeter (TASC) for a total thickness of 30 X$_{0}$ and 1.3 proton interaction length. A dedicated module (a charge detector, CHD), placed at the top of the apparatus, identifies the atomic number Z of the incoming cosmic ray, while the IMC provides tracking capabilities and a redundant charge identification by multiple dE/dx measurements. In this paper, the expected performances of the tracking and charge identification systems of CALET will be discussed. The CALET mission is funded by the Japanese Space Agency (JAXA), the Italian Space Agency (ASI), and NASA.
Speaker: Paolo Brogi (Universita degli studi di Siena (IT))
• 3:30 PM
CALET perspectives for calorimetric measurements of high energy electrons based on beam test results 1h
CALET is a space mission currently in the final phase of preparation for a launch to the International Space Station (ISS), where it will be installed on the Exposure Facility of the Japanese Experiment Module (JEM-EF). One of the main science goals of the experiment is the measurement of the inclusive electron (+positron) spectrum. By integrating a sufficient exposure on the ISS, CALET will be able to explore the energy region above 1 TeV, where the presence of nearby sources of acceleration is expected to shape the high end of the electron spectrum and leave faint, but detectable, footprints in the anisotropy. In order to meet this experimental goal, CALET has been designed to achieve a large proton rejection capability (>$10^5$) thanks to a full containment of electromagnetic showers in a 27 X$_0$ thick calorimeter (TASC) preceded by a 3 X$_0$ fine-grained pre-shower calorimeter (IMC) with imaging capabilities. In this paper the expected performance of the instrument with electrons will be discussed on the basis of the results of measurements performed during beam calibration tests at CERN-SPS at beam energies up to 290 GeV.
Speaker: Gabriele Bigongiari (Universita degli studi di Siena (IT))
• 3:30 PM
Calibration and sensitivity of large water-Cherenkov Detectors at the Sierra Negra site of LAGO 1h
The Latin American Giant Observatory (LAGO) is an international network of water-Cherenkov detectors (WCD) set in different sites across Latin America. In México, on the top of the Sierra Negra volcano at 4530 m a.s.l., LAGO has completed its first instrumented detector of an array, consisting of a cylindrical WCD with 7.3 m in diameter and 1 m of height, with a total detection area of $40$ m$^2$ and sectioned in four equal slices. Each one of these slices is instrumented with an 8" photo-multiplier tube installed at the top of the detector and looking downwards. The final setup will have three WCD as the one mentioned, distributed in triangular shape and one WCD with 7.3 m in diameter and 5 m of height located in the centre. The data acquisition of this first WCD started in June 2014. In this work the full calibration procedure of this detector will be discused, as well as the report on the preliminary measurements of stability in rate. Effective area and sensitivity to gamma-ray bursts are derived from the LAGO simulation chain, based on Magnetocosmics, CORSIKA and GEANT4. From these results, we discuss the capability of this detector to separate the EM-muon component of extensive air showers.
Speaker: Dr Alberto Carramiñana Alonso (INAOE)
• 3:30 PM
Calibration of a fluorescence detector using a flying standard light source for the Telescope Array observatory 1h
The main calibration items of Fluorescence Detector (FD) observation are the fluorescence yield, the atmospheric attenuation and the detector sensitivity. In 2012-2013, we conducted a joint TA-Auger calibration campaign by a flying device mounted with an ultraviolet LED as a standard light source. This device is called an octocopter, and was built by KIT. An octocopter has excellent portability and is suitable for calibration for FDs at a variety of remote locations. In TA FD observation of the octocopter, a difference in the number of detected photons between measurement and simulation is ± 5%, in the range of systematic error of the light source. In TA, we have begun developing a similar flying standard light source.　 By mounting a high-performance GPS, the systematic errors of the measured light source position will be improved to less than 1 m. A photodiode mounted directly near the light source measures the relative light intensity of each pulse. We report the progress of development for the octocopter, and the analysis results of the joint calibration campaign using the previous octocopter.
Speaker: Mr Motoki Hayashi (Shinshu University)
• 3:30 PM
Calibration of the absolute amplitude scale of the Tunka Radio Extension (Tunka-Rex) 1h
The Tunka Radio Extension (Tunka-Rex) is an array of 44 radio antenna stations, constituting a radio detector for air showers. It is an extension to Tunka-133, an air-Cherenkov detector in Siberia, which is used as an external trigger for Tunka-Rex and provides a reliable reconstruction of energy and shower maximum. Each antenna station consists of two perpendicularly aligned active antennas, called SALLAs. An antenna calibration of the SALLA with a commercial reference source enables us to reconstruct the incoming radio signal on an absolute scale. Since the same reference source was used for the calibration of LOPES and, in a calibration campaign in 2014, also for LOFAR, these three experiments now have a consistent calibration and, therefore, absolute scale. This was a key ingredient to resolve a longer standing contradiction between measurements of two calibrated experiments. We will present how the calibration was performed and compare radio measurements of air showers from Tunka-Rex to model calculations and published results from other calibrated experiments.
Speaker: Roman Hiller (KIT)
• 3:30 PM
Calibration of the LOFAR antennas 1h
Extensive air showers create short nanosecond-scale pulses in the radio frequencies. These pulses have been measured successfully in the past years at the Low-Frequency Array (LOFAR). Due to the short duration and emission of the signal in the atmosphere, methods based on flux calibration of known sources as used in radio astronomical observations cannot be applied to establish an absolute calibration. To overcome this, we present three approaches that were used to check and improve the antenna model of LOFAR, and to provide an absolute calibration for air shower measurements. In future work these results can be used as an absolute scale for measurements of astronomical transients with LOFAR.
Speaker: Jörg Hörandel (Ru Nijmegen/Nikhef)
• 3:30 PM
Calibration of the TA Fluorescence Detectors with Electron Light Source 1h
The Electron Light Source (ELS) is a linear accelerator used to perform energy calibration of the fluorescence detectors (FD) in the Telescope Array experiment. The ELS shoots a beam of 40 MeV electrons into the atmosphere 100 m in front of the Black Rock Mesa FD. Air fluorescence light is detected from nitrogen molecule excitation by the ELS electron beam. An end-to-end calibration from generation of fluorescence by air to detection of fluorescence photon by FD PMT camera is achieved. We present the calibration method and the comparison between beam data and Monte Carlo simulation.
Speaker: Bokkyun Shin (Hanyang University)
• 3:30 PM
Cascade showers initiated by muons in the Cherenkov water detector NEVOD 1h
Measurements of the energy spectra of cascade showers generated due to interactions of penetrating cosmic ray particles in massive water/ice detectors is one of the main methods of the study of the energy characteristics of the fluxes of muons and neutrinos. In the present paper, results of investigations of cascades initiated by inclined muons in the Cherenkov water detector NEVOD with a volume of 2000 m^3, located at the ground surface and equipped with a spatial lattice of 91 quasi-spherical modules (QSMs), detecting Cherenkov light from any direction with nearly equal efficiency, are discussed. A brief description of the setup features is given. The approaches to the reconstruction of energy and spatial parameters of the showers registered in a dense lattice of QSMs, and questions of the absolute calibration of the QSM response are considered. Preliminary results of the measurements of the energy spectrum of the cascades in the energy range 30 GeV – 10 TeV based on the data accumulated in 2013 – 2015 experimental series (about 11,000 live observation time) and their comparison with expectation for some models of the muon energy spectrum are presented.
Speaker: Prof. Rostislav Kokoulin (National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
• 3:30 PM
CORSIKA modification for rigidity dependent primary selection based on Geomagnetic cutoff rigidity for GRAPES-3 simulations 1h
For the analysis of the GRAPES-3 Muon data, large scale Monte Carlo simulations are required. These simulations are performed using the CORSIKA simulation package developed by the KIT group. However, the geomagnetic cutoff rigidity varies with direction, therefore, a constant threshold for selection of primary energy results in generation of a large number of events that are subsequently rejected due to their rigidity being below the cutoff value in some directions. We have implemented an efficient mechanism in CORSIKA to select only those primary cosmic rays that lie above the cutoff rigidity in a given direction resulting in rejection of those primary cosmic rays that would have otherwise been rejected subsequently. Results based on actual simulations of GRAPES-3 Muon data have shown that by using this rigidity based cut, the actual computation time was reduced by a factor of two without compromising the reliability of the results.
Speaker: Mr Hari Haran Balakrishnan (HECR Group, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India and GRAPES-3 Experiment, Cosmic Ray Laboratory, Ooty 643 001, India)
• 3:30 PM
Cosmic Ray Shower Profile Track Finding for Telescope Array Fluorescence Detectors 1h
A simple cosmic ray track finding pattern recognition analysis (PRA) method for fluorescence detectors (FD) has been developed which significantly improves Xmax resolution and its dependence on energy. Events which have a clear rise and fall in the FD view contain information on Xmax that can be reliably reconstructed. Shower maximum must be extrapolated for events with Xmax outside the field of view of the detector, which creates a systematic dependence on the fitting function. The PRA method is a model and detector independent approach to removing these events, by fitting shower profiles to a set of triangles and applying limits on the allowable geometry.
Speaker: Mr Jon Paul Lundquist (Telescope Array Project)
• 3:30 PM
Cosmic-ray positron measurements: on the origin of the e+ excess and limits on magnetar birthrate 1h
Positrons were discovered in cosmic rays 50 years ago. During the last 25 years, reliable magnetic spectrometer observations consistently revealed an excess of these particles above a few GeV with respect to the expected secondary component. The most recent measurements of the positron flux and the e+/(e++e-) ratio carried out by the Pamela and AMS experiments confirm the average trend of previous magnetic spectrometer observations up to 50 GeV and indicate that this excess is observed up to about 500 GeV. Many different hypotheses were suggested in the literature to explain these observations. However, when the characteristics of possible sources of e+ are taken into account, astrophysical objects and in particular, pulsars and, possibly, magnetars, remain the most plausible candidates even if disk formation may critically affect the actual contribution of these stars to cosmic-ray positrons. The magnetar birthrate is revised within the proposed scenario.
Speaker: Catia Grimani (University of Urbino "Carlo Bo")
• 3:30 PM
Data Accessibility, Reproducibility and Trustworthiness with LAGO Data Repositories 1h
Nowadays, one of the most challenging scenarios scientists and scientific communities are facing is the huge amount of data emerging from vast networks of sensors and from computational simulations performed in a diversity of computing architectures and e-infrastructures. In this work we present the strategy of the Latin American Giant Observatory (LAGO) to catalog and preserve a vast amount of data produced by the water-Cherenkov Detector network and the complete LAGO simulation chain that characterize each site. Metadata, Permanent Identifiers and the facilities from the LAGO Data Repository are described. These initiatives allow researchers to find data and directly use them in a code running by means of a Science Gateway that provides access to different clusters, Grid and Cloud infrastructures worldwide.
Speaker: Dennis Cazar Ramírez (Universidad San Francisco de Quito)
• 3:30 PM
Development of a High Altitude LAGO Site in Peru 1h
The Latin American Giant Observatory (LAGO) Project is an extended Cosmic Ray Observatory mainly oriented to perform basic research in three branches: high energy phenomena, space weather and atmospheric radiation at ground level. To observe the high energy component (over 10 GeV) of Gamma Ray Bursts (GRBs), the LAGO Collaboration is installing Water Cherenkov Detectors (WCDs) in high altitude sites. Extensive Air Showers (EAS) produced in the atmosphere by GRBs high energy photons could be detected by WCD arrays given their good sensitivity to secondary photons and other particles in the cascades, by looking for excesses over the secondary particle flux. In this work the current developments to build and characterize a high altitude ($>4600$ m a.s.l.) LAGO site in the central highlands of Peru are described.
Speaker: Stephany Vargas (Escuela Politécnica Nacional)
• 3:30 PM
Development of a high efficient PMT Winston-cone system for fluorescence measurement of extensive air showers 1h
Fluorescence telescopes are an important technique to measure extensive air showers initiated by ultra-high energetic cosmic rays. They detect the longitudinal profile of the energy deposited in the atmosphere by the de-excitation of nitrogen molecules in the UV-range. In the past years the development of photomultiplier tubes (PMT) has led to an increase of more than $30\%$ in photon detection sensitivity, by using new super-bialkali (SBA) photocathodes. Thus, the telescopes can detect even fainter signals over a farther area with a significant increase in aperture. To develop a telescope for a next generation cosmic ray observatory, a camera needs to have a maximal sensitive area of the focal plane. Winston-cones can efficiently cover the dead area between the photocathode of the PMTs. Such a highly efficient system composed of a SBA PMT and Winston cone has been developed based on the design of the fluorescence telescopes of the Pierre Auger Observatory. This contribution shows the development of the optical detection system and first tests in one of the fluorescence telescopes.
Speaker: Karl-Heinz Kampert (Universität Wuppertal)
• 3:30 PM
Development of the TALE Surface Detector Array 1h
TALE, the Telescope Array Low Energy extension is designed to lower the energy threshold to about $10^{16.5}$ eV. The TALE surface detector will include an infill array of 76 scintillation counters (40 with 400 m spacing and 36 with 600 m spacing) and an addition to the TA SD of 27 counters. We have already deployed 35 counters with 400 m spacing in April 2013. For the additional 68 counters, we will use refurbished AGASA scintillation counters, each of which consists of AGASA scintillators, a new PMT and an improved the Telescope Array surface detector electronics. Here we report the status of the detectors and simulation.
Speaker: Shoichi Ogio (Osaka City University)
• 3:30 PM
Development of the Waseda CALET Operations Center (WCOC) for Scientific Operations of CALET 1h
The CALET project aims at a long duration observation of high energy cosmic rays onboard the International Space Station (ISS). The CALET detector features a very thick calorimeter of 30 radiation-lengths which consists of imaging and total absorption calorimeters. It will directly measure the cosmic-ray electron spectrum in the energy range of 1GeV--20TeV with 2-% energy resolution. The data obtained with CALET onboard ISS will be transferred to JAXA using two data relay satellite systems operated by NASA and JAXA, respectively. To operate the CALET onboard ISS, the CALET Ground Support Equipment (CALET-GSE) is being prepared in JAXA. Simultaneously, Waseda CALET Operations Center (WCOC) is being established to perform operations and monitoring related to the scientific mission. The real-time data received by CALET-GSE is immediately transferred to WCOC. Scientific raw data are also transferred to WCOC on an hourly basis after time-order correcting and complementing replay data. Mission operations at WCOC includes (1) real-time monitoring and operations, (2) operations planning, and (3)and processing raw, level-0, scientific data to level-1 data that will be used for scientific analysis. In this paper we will review the role of WOCC and report on its development.
Speaker: Yoichi Asaoka (Waseda University (JP))
• 3:30 PM
Diffusion and Anisotropy of Cosmic Rays in the Galaxy: Beyond the Dipole 1h
The transport of Galactic cosmic rays in both turbulent and regular magnetic fields can be described in terms of diffusion and drift motions. These produce gradients of cosmic-ray densities. The anisotropy resulting from these gradients for an observer located anywhere in the Galaxy is commonly described in terms of a pure dipole moment, the amplitude of which is proportional to the gradient at the observer point normalised by the density at the same observer point. By calculating the angular distribution on the sphere of the observer in the specific case of cosmic rays propagating diffusively from a single source, we show that this recipe to estimate the dipole moment is only an approximation, and that higher order moments are actually also expected. Since a dipole moment is by essence a vector, it is conceivable to build configurations of sources where the global vector cancels even with a non-vanishing gradient of cosmic-ray density. In this case, the non- vanishing gradient would show up at higher order moments that do not add linearly, such as the moment describing a symmetric quadrupole. Although the dipole moment is expected to remain dominant for an observer located on Earth and for sources distributed in the Galactic disk, the description given in this paper of the anisotropy expected within a pure diffusion model could contribute to some extent to explain the observed anisotropies of low-energy cosmic rays beyond the dipole.
Speaker: Olivier Deligny (CNRS/IN2P3)
• 3:30 PM
Education, Outreach and Public Relations of the Pierre Auger Observatory 1h
The scale and scope of the physics studied at the Pierre Auger Observatory continue to offer significant opportunities for original outreach work. Education, outreach and public relations of the Auger Collaboration are coordinated in a dedicated task whose goals are to encourage and support a wide range of efforts that link schools and the public with the Auger scientists and the science of cosmic rays, particle physics, and associated technologies. The presentation will focus on the impact of the Collaboration in Mendoza Province, Argentina and beyond. The Auger Visitor Center in Malarg\"{u}e has hosted over 95,000 visitors since 2001, and a fifth collaboration-sponsored science fair was held on the Observatory campus in November 2014. The Rural Schools Program, which is run by Observatory staff and which brings cosmic-ray science and infrastructure improvements to remote schools, continues to broaden its reach. Numerous online resources, video documentaries, and animations of extensive air showers have been created for wide public release. Increasingly, collaborators draw on these resources to develop Auger related displays and outreach events at their institutions and in public settings to disseminate the science and successes of the Observatory worldwide. The presentation will also highlight education and outreach activities associated with the planned upgrade of the Observatory’s detector systems and future physics goals.
Speaker: Dr Charles Timmermans (Nikhef/Radboud University)
• 3:30 PM
Effects of Turbulent Magnetic Fields in Cosmic Ray Ansiotropy 1h
Cosmic ray anisotropy has been observed to be present in a wide energy range by a variety of experiments such as Milagro and the IceCube Observatory. However, a satisfactory explanation has been elusive for more than fifteen years now. A possible solution for the TeV-PeV cosmic ray anisotropy is the introduction of turbulent magnetic interactions on the arrival direction. We perform test particle simulations in compressible magnetohydrodynamic turbulence to study how cosmic rays’ arrival direction distribution is perturbed when they stream along the local turbulent magnetic field. In this work, we discuss the effects arising from propagation in this inhomogeneous and turbulent interstellar magnetic field.
Speaker: Paolo Desiati (University of Wisconsin - Madison)
• 3:30 PM
ELLIPTIC FLOW in nuclear interaction of astroparticle at energy $10^{16}$ eV. 1h
107 cascades, created by secondary particles of astroparticle interaction at $10^{16}$ eV, were detected in the stratospheric emulsion chamber. Their azimuth distribution reveals a distinct anisotropy. Estimation of the elliptic flow coefficient v2 gives a value 0.35 $\pm$ 0.02. The distribution of cascade p(t) is also azimuth anisotropic and its maximal value coincides with the direction of the impact parameter.
Speaker: OLEG DALKAROV (P.N.Lebedev Physical Institute)
• 3:30 PM
Energy Spectrum and Mass Composition of Ultra-High Energy Cosmic Rays Measured by the hybrid technique in Telescope Array 1h
The energy spectrum and mass composition of Ultra-High Energy Cosmic Rays (UHECRs) measured using a hybrid analysis will be presented. TA consists of three FD stations and 507 SDs. A hybrid analysis reconstructs the position and direction of the air shower more accurately than the monocular FD analysis and measures the longitudinal development and calorimetric energy of the shower precisely. Information of the mass composition of UHECR, Xmax, is obtained from the measured longitudinal development. The analysis performance, energy spectrum and mass composition of the UHECR obtained from the TA hybrid mode will be presented.
Speakers: Daisuke Ikeda (Institute for Cosmic Ray Research, University of Tokyo), Dr William Hanlon (University of Utah)
• 3:30 PM
Energy Spectrum and Mass Composition of Ultra-High Energy Cosmic Rays Measured with the Telescope Array Fluorescence Detector Using a Monocular Analysis 1h
The Telescope Array (TA) experiment is the largest hybrid detector to observe ultra-high energy cosmic rays (UHECRs) in the northern hemisphere. We report on results of the energy spectrum of UHECRs covering a wide energy range, and the mass composition using the maximum shower depth, from analyzing data collected in monocular mode by the fluorescence detectors of TA during the first seven years.
Speaker: Toshihiro FUJII (University of Chicago, University of Tokyo)
• 3:30 PM
ENERGY THRESHOLD DETERMINATION FOR AMIGA MUON COUNTERS VIA GEANT4 SIMULATION 1h
One of the first improvements of the Pierre Auger Observatory is the Auger Muons and Infill for the Ground Array (AMIGA) detector, in order to measure the cosmic ray spectrum and the chemical composition in the energy range from $10^{17}$eV. The muon detectors of the AMIGA *infill* count muons from extensive air showers observed by Auger Observatory, which are then reconstructed by the surface and fluorescence detectors. Muons with energy greater than or equivalent to 1 GeV propagating in the soil are able to reach the muon detector. Although the air shower muonic component is attenuated much less than the electromagnetic component, the shielding of approximately 2.25 m of soil adds 540 g/cm$^{2}$ of vertical mass (approximately 60% more than the atmosphere above the Pierre Auger Observatory). Thus, in order to better understand attenuation mechanisms (shielding effects) of muons, a Monte Carlo simulation with Geant4 was made to determine the muon energy threshold, i.e., the minimum kinetic energy the muon should have to go through the 2.25 m of soil and produce a signal in the AMIGA counters. The energy threshold is determined by taking into account the primary particle as well as the secondary particles produced in the soil above the detector. The information on the energy threshold is important to understand the process of data analysis. This threshold can be used to test the Geant4 simulation program, since the muon energy threshold is well calculated via the Bethe-Bloch formula. From the energy thresholds and the energy distribution at ground level for different particles from extensive air showers, the contribution of those particles to the data recorded by the detectors can be calculated. This contribution is crucial to correctly determine the number of muons in an extensive air shower, which is one of the main aims of the AMIGA enhancement. Keywords: AMIGA detectors, Geant4 simulation, muons, energy threshold, Bethe-Bloch formula.
Speaker: Mr Luiz Augusto Stuani Pereira (Unicamp)
• 3:30 PM
Experimental method to measure the positron and electron fluxes in AMS-02 1h
The Alpha Magnetic Spectrometer AMS-02 is a high energy particle physics detector, operational on the International Space Station since May 2011. The AMS-02 goal is the fundamental physics research in space with high energy cosmic rays, during its 20 year duration mission. The latest published results, with 30 months of data, show an excess of high energy positrons whose origin is still highly uncertain. These positrons, in addition to being produced by spallation of cosmic rays on interstellar medium, may be produced in nearby pulsars, annihilation of Dark Matter particles, or still unknow processes. In this poster, I will review the analysis technique used for measuring positron flux and electron flux, as well as positron fraction. This analysis is based on three subdetectors: the Transition Radiation Detector (TRD), the silicium tracker, and the Electromagnetic Calorimeter (ECal). I will present a method which allows the combination of estimators constructed from these three subdetectors, in order to separate first leptons and protons, and secondly positrons and electrons. I will also detail the influence and the determination of the charge confusion between the positrons and electrons at high energy. The positron and electron flux, as well as the positron fraction, will be shown and discussed.
Speaker: Sami Caroff (Centre National de la Recherche Scientifique (FR))
• 3:30 PM
FAMOUS - A fluorescence telescope using SiPMs 1h
The FAMOUS telescope is a prove-of-concept study for the usage of silicon based photo sensors (SiPMs) in fluorescence telescopes. Such telescopes detect the fluorescence light emitted by ultra-high energy cosmic ray particles impinging on the Earth's atmosphere. Available instruments, like the fluorescence telescopes of the Pierre Auger Observatory in Argentina, are using photo multiplier tubes for photon detection. The FAMOUS camera aims to make use of the advantages of recent developments in photo detection by SiPM sensors, like increasing the duty cycle due to the ability to operate SiPMs under bright moon light. Build in a 50 cm-diameter aluminum tube, and employing refractive optics driven by a Fresnel-lens, a seven-pixel prototype camera has been installed and developed. First results look very promising. The next stage of the prototype will be equipped with a 61-pixel camera, a more lightweight tube, more efficient light concentrators, and a customized and more stable power supply. The results of the test measurements and the status of the next stage prototype will be presented.
Speaker: Thomas Bretz (RWTH Aachen)
• 3:30 PM
Heavy ion beam test at CERN-SPS with the CALET Structure Thermal Model 1h
We will report testing and calibration of the heavy-ion energy and charge resolution of the CALET cosmic-ray instrument that will fly on the International Space Station in 2015. The beam tests were carried out using a test instrument that is functionally equivalent to CALET. CALET will measure the energy spectra and arrival directions of cosmic-ray electrons to 20 TeV and hadrons to 1 PeV with exceptional resolution. It will measure the spectra of high-energy nuclei to about Z=40. It will also measure the cosmic gamma radiation with superior resolution to search for signatures of dark matter annihilation in the gamma-ray and electron spectra. We preformed beam tests at CERN-SPS in February and March 2015 to calibrate energy, angular and charge resolution with direct primary beams and secondary fragments of Ar of 13, 19, and 150 A GeV/c. The beam tests were carried out using a test instrument that is functionally equivalent to the calorimeter (CAL) of CALET. I will present our ion run purpose and experimental method and setups, and preliminary results.
Speaker: Tadahisa Tamura (Kanagawa University (JP))
• 3:30 PM
High $p_\mathrm{T}$ muons from cosmic ray air showers in IceCube 1h
Cosmic ray air showers with primary energies above $\sim 1$ TeV can produce muons with high transverse momentum ($p_\mathrm{T} > 2$ GeV). These isolated muons can have large transverse separations from the shower core up to several hundred meters. Together with the muon bundle they form a double track signature in km$^3$-scale neutrino telescopes such as IceCube. These muons originate from the decay of heavy hadrons, pions, and kaons produced very early in the shower development, typically in (multiple) high $p_\mathrm{T}$ jets. If high $p_\mathrm{T}$ muons are produced simultaneously in two jets that are oriented back-to-back such interactions can also produce distinctive triple track signatures in IceCube. The separation from the core is a measure of the transverse momentum of the muon’s parent particle and the muon lateral distribution depends on the composition of the incident nuclei. Hence, the composition of high energy cosmic rays can be determined from muon separation measurements. Moreover for $p_\mathrm{T} > 2$ GeV particle interactions can be described in the context of perturbative quantum chromodynamics (pQCD) which can be used to calculate the muon lateral separation distribution. Thus these muons may help to test pQCD predictions of high energy interactions involving heavy nuclei. We discuss the contributions from different components of air showers to the high $p_\mathrm{T}$ muon flux. Based on dedicated simulations the prospects of composition measurements using high $p_\mathrm{T}$ muons in km$^3$-scale neutrino telescopes are studied. We present analysis methods to study laterally separated muons in IceCube with lateral separations larger than 150 m using data taken from May 2012 to May 2013
Speaker: Mr Dennis Soldin (University of Wuppertal)
• 3:30 PM
Improving the universality reconstruction using independent measurements of water-Cherenkov detectors and additional muon counters 1h
Shower universality has demonstrated to be a sturdy tool to describe particle showers produced by primary cosmic rays. The secondary particles at the observation level can be described by a four component model: the well known electromagnetic and muonic components, the contribution due to the electromagnetic halo of the muons, and the electromagnetic particles originating from pion decays close to ground following closely the development of the muonic component. Due to the high amount of particles produced, those distributions can be described within three parameters: The total energy $E$, the depth of shower maximum $X_{\rm max}$, and the muon content $N_{\mu}$. The energy and $X_{\rm max}$ are governed by the pure electromagnetic component, while the muon scale ($N_{\mu}$) gives cause to differences between hadronic interaction models and primary particles, affecting the three remaining components. Though predictions on these macroscopic parameters are already viable with a single detector type (e.g. an array of water-Cherenkov detectors), large correlations between the quantities are apparent and need to be taken into account when interpreting the data. To overcome the degeneracy, additional muon counters allow for an independent measurement of the muon number at ground and at the same time reduce systematic uncertainties due to the hadronic interaction model used. The procedure is exemplified for the case of the Pierre Auger Observatory by parameterizing the signal response of particles in the water-Cherenkov array operating with underground muon detectors. The universal parameterizations allow us to estimate independently the $E$ and $N_{\mu}$ on an event-by-event basis. The incorporation of muon detectors evidences e.g. the possibility of an unbiased energy estimation based only on the universality description of the shower.
Speaker: Markus Roth (KIT)
• 3:30 PM
In-flight operations and status of the AMS-02 silicon tracker 1h
The AMS-02 detector is a large acceptance magnetic spectrometer operating on the International Space Station since May 2011. More than 60 billion events have been collected by the instrument as of today. One of the key subdetectors of AMS-02 is the silicon microstrip Tracker, designed to precisely measure the trajectory and absolute charge of cosmic rays in the GeV-TeV energy range. In addition with the magnetic field is also measuring the particles rigidity and the sign of the charge. This report presents the Tracker online operations and calibration during the first four years of data taking in space. The track reconstruction efficiency and the resolution will be also reviewed.
Speaker: Xiaoting Qin (Universita e INFN, Perugia (IT))
• 3:30 PM
Inelastic and diffractive cross section measurements with the CMS experiment 1h
The inelastic cross section has been measured in proton-proton and proton-lead collisions at centre-of-mass energies per nucleon up to 8 TeV at the LHC. Nuclear scaling effects play an important role in the simulation of cosmic ray interactions and are studied in collisions with lead nuclei. Furthermore, the probability of diffractive interactions influences the efficiency of the energy transport in extensive air showers and, thus, for example the depth of the shower maximum. We present an overview of the related results published by the CMS Collaboration.
Speaker: Colin Baus (KIT - Karlsruhe Institute of Technology (DE))
• 3:30 PM
Initial results of a direct comparison between the Surface Detectors of the Pierre Auger Observatory and of the Telescope Array 1h
The Pierre Auger Observatory (Auger) in Mendoza, Argentina and the Telescope Array (TA) in Utah, USA aim at unraveling the origin and nature of Ultra-High Energy Cosmic Rays (UHECR). At present, there appear to be subtle differences between Auger and TA results and interpretations. Joint working groups have been established and have already reported preliminary findings. From an experimental standpoint, the Surface Detectors (SD) of both experiments makes use of different detection processes not equally sensitive to the components of the extensive air showers making it to the ground. In particular, the muonic component of the shower measured at ground level can be traced back to the primary composition, which is critical for understanding the origin of UHECRs. In order to make direct comparisons between the SD detection techniques used by Auger and TA, a two-phase approach is followed. First, one water Cherenkov detector (“Auger North” design) was deployed and operated locally at the TA Central Laser Facility. After a couple of months of operation before the summer, we expect to observe about 20 Auger SD events in coincidence with nearby TA stations. And a regular Auger station and a TA station will be added to the setup to allow for station-level comparisons. In a second phase, event-level comparisons of relatively low-energy showers with energies in the 10$^{18}$ eV range will be possible as a result of co-locating six additional Auger North stations contiguous to TA surface detector stations. In this contribution, we present the status and prospects of this joint research project, including the first Auger SD data that were recorded in coincidence with the TA SD shower triggers.
Speaker: Ryuji Takeishi (Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba, Japan)
• 3:30 PM
Investigation of angular distributions in the interaction of cosmic-ray particles with a dense target and comparison with data of the Large Hadron Collider. 1h
Cosmic ray measurements are carried out on at a detector station located in the Tian Shan mountains at an altitude of 3340 meters above sea level using the complex installations "Hadron-9" and "Hadron-44". The main objective of these studies is the interaction of cosmic rays with nuclei, in particular the study of anomalous events occurring in the cores of extensive air showers (EAS). Analysis was performed for 10199 detected events, of which 2657 events interacted directly in the target. 462 events with a Gamma-ray number of n≥4 could be identified. For these events angular correlations were investigated using two-dimensional correlation functions of the form Δη-Δφ. Here Δη is the difference of pseudorapidities (η= -ln(tan(θ/2)) with θ the polar angle measured by the deviation from the beam axis deviation, and Δφ is the difference between the azimuth angles of two particles. As a result we received a well-defined structure for the paired 0.5 < Δη < 4.5, 0.4 < Δφ < 2.6 two-particle correlation functions, almost similar to the results obtained in the “Observation of long-range, near-side angular correlations in proton-proton collisions at the LHC”. This is the first observation of such a structure in the two-particle correlation function of the interaction of cosmic rays with matter.
Speaker: Yernar Tautayev (Institute of Physics and Technology, Almaty, Kazakhstan)
• 3:30 PM
Investigation of the energy deposit of inclined muon bundles in the Cherenkov water detector NEVOD 1h
An excess of multi-muon events in comparison with simulations performed in frame of widely used hadron interaction models was found in several cosmic ray experiments at very- and ultra-high energies of primary particles. In order to solve this so-called ‘muon puzzle’, investigations of the energy characteristics of EAS muon component are required. A possible approach to such investigations is the measurement of the energy deposit of EAS muons in the detector material: the appearance of an excessive fraction of very high-energy muons should be reflected in the dependence of the energy deposit on the energy of primary particles. The experiment on the study of the energy deposit of muon bundles is being conducted at the NEVOD-DECOR experimental complex. As a measure of the energy deposit, the sum of the responses of quasi-spherical modules of the Cherenkov calorimeter NEVOD is used. The local muon density in the event and the muon bundle arrival direction are estimated from the data of coordinate-tracking detector DECOR. Registration of inclined muon bundles of different multiplicities at various zenith angles allows to evaluate primary particle energies and to explore the energy interval from ~ 10^16 to 10^18 eV. Experimental data accumulated from May 2012 to April 2015 (about 17,000 hours live observation time) have been analyzed and compared with CORSIKA based simulations. It is found that the average specific energy deposit (i.e., the calorimeter response normalized to the local muon density in the events) appreciably increases with zenith angle, thus reflecting the increase of the muon energy in the bundles near horizon. An evidence for an increase of the energy deposit at primary energies above 10^17 eV is seen in the measured dependence of the specific energy deposit on the muon density. Possible methodical and physical reasons of such anomalous behavior are analyzed.
Speaker: Prof. Igor Yashin (National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
• 3:30 PM
Investigation of the flux of albedo muons with NEVOD-DECOR experimental complex 1h
Results of investigation of the near-horizontal muons are presented in the range of zenith angles of 85 – 95 degrees. In this range, so-called ‘albedo’ muons (atmospheric muons scattered in the soil into the upper hemisphere) are detected. Measurements have been conducted with the NEVOD-DECOR experimental complex located on the campus of MEPhI. The basis of the complex is the Cherenkov water detector NEVOD with the volume of 2000 m^3 equipped with a dense spatial lattice of quasi-spherical modules (91 in total). Each module consists of six FEU-200 PMTs with flat photocathodes directed along the axes of the orthogonal coordinate system. The coordinate detector DECOR is deployed around the NEVOD. DECOR includes eight vertically suspended eight-layer assemblies of plastic streamer tube chambers with resistive cathode coating with the total sensitive area 70 m^2. Chamber planes are equipped with two-coordinate external strip readout system. Detector DECOR allows to localize tracks of a near-horizontal muons with high angular (better than 1 degree) and spatial (about 1 cm) accuracy and allows to determine the muon direction by time-of-flight technique with probability of error of the order 10^-2. More reliably, muon direction can be obtained from the NEVOD data using the directionality of Cherenkov light. The combination of these two independent methods allows to determine the muon direction with the probability of error less than 10^-8. The results of the measurements of the flux of albedo muons for experimental series with the duration of about 20,000 hours ‘live’ time and comparison of them with different models of muon scattering in soil are presented.
Speaker: Dr Semen Khokhlov (National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
• 3:30 PM
LARGE-SCALE ANISOTROPY OF TeV-BAND COSMIC RAYS 1h
The expected anisotropy in the 1 to 104 TeV energy range is calculated for Galactic cosmic rays with both anisotropy in the diffusion tensor and source discreteness taken into account.We find that if the sources are distributed radially (but with azimuthal symmetry) in proportion to Galactic pulsars, the expected anisotropy almost always exceeds the observational limits by one order of magnitude in the case of isotropic diffusion. If the radial diffusion is more than an order of magnitude smaller than the azimuthal diffusion rate, the radial gradient of the sources can be accommodated about 5% of the time. If the sources are concentrated in the spiral arms, then the anisotropy depends on our location between them, but in some spatial window, roughly equidistant from adjacent spiral arms, the observational constraints on anisotropy are obeyed roughly 20%–30% of the time for extremely anisotropic diffusion. The solar system is in that window less than 10% of the time, but it may be there now. Under the assumption of isotropic diffusion, nearby supernovae are found to produce a discreteness anisotropy that is nearly two orders of magnitude in excess of the observational limit if all supernovae are assumed to contribute equally with a source rate 1 in every 100 years
Speaker: Rahul Kumar (Ben Gurion University)
• 3:30 PM
LHAASO-KM2A PMT test 1h
To fulfill the requirements of testing the photomultiplier tubes (PMTs) of the electromagnetic detector at the Large High Altitude Air Shower Observatory, a multifunctional PMT test bench with a two-dimensional (2D) scanning system is developed. With this 2D scanning system, 16 PMTs are scanned simultaneously to test their uniformity and cathode transit time difference. The di-distance method is developed to measure the linear dynamic range of the PMTs using the test bench. The primary test results are presented.
Speaker: Sun Zhandong (Southwest Jiaotong University)
• 3:30 PM
LHAASO-WFCTA Optical System Optimization for High Precision Cherenkov Shower Reconstruction 1h
Wide Field-of-view air Cherenkov Telescope Array (WFCTA) is an essential component of the Large High Altitude Air Shower Observatory (LHAASO). WFCTA comprises 24 movable identical telescopes specialized for measuring the energy spectrums of the cosmic ray ingredients. In this paper, we describe the synthesis optimization design of the optical system, including the mirror segments, the camera and the Winston cone light collectors for individual telescope. We also evaluate the imaging performance through Monte Carlo simulation as well as spot scanning experiments. Finally, based on these properties, a high precision Cherenkov image reconstruction technique is discussed, which is implemented to improve the imaging resolution so as to fulfill the precise Cherenkov shower reconstruction.
Speaker: Dr Chong Wang (Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences)
• 3:30 PM
Lightning Detection at the Pierre Auger Observatory 1h
As part of the Auger Engineering Radio Array, an extension of the Pierre Auger Observatory with antennas in the MHz range, it is necessary to monitor the local atmospheric conditions. These have a large influence on the radio emission induced by air showers. In particular, amplified signals up to an order of magnitude have been detected as an effect of thunderstorms. For a more detailed investigation and the detection of thunderstorms, a new lightning detection system has been installed at the Pierre Auger Observatory in Argentina. In addition, an electric field mill measures the electric field strength at ground level at the antenna array. With these measurements, data periods can be classified for their influence by thunderstorms. Additionally, a lightning-based trigger for the water-Cherenkov detectors was developed to read individual stations when lightning strikes nearby. With these data a possible correlation between the formation of lightning and cosmic ray showers can be investigated even at low energies of about $10^{15}$ eV. In this talk the structure and functionality of the lightning detection system are described, and first data analyses are shown.
Speaker: Karl-Heinz Kampert (Universität Wuppertal)
• 3:30 PM
Local density spectra of electron and muon EAS components in primary energy range from 10^14 to 10^18 eV 1h
The system of calibration telescopes (SCT) of the Cherenkov water detector (CWD) NEVOD is used as a shower array. SCT consists of two planes (80 m^2) with 40 scintillation counters (40×20×2 cm^3) in each. One plane is located on the roof of the CWD, and another one on its bottom. The distance between two planes is 9.45 m. Each registration channel of SCT is able to evaluate the counter response amplitude in the range from ~1 to ~50 relativistic particles, which corresponds to electron densities up to ~500 particles/sq.m. The triggering system identifies three types of events in SCT. The telescope trigger allows selecting muon tracks for calibration of the CWD photomultipliers and scintillation counters themselves. Other two triggers provide registration of the multiparticle events in each plane of SCT. The top plane is used as a detector of electron component of EAS, and the bottom one provides registration of the EAS muon bundles. The technique of EAS investigations with the SCT is based on the phenomenology of local density of charged particles because each plane of the setup has an area much less than transverse sizes of EAS. We have measured the spectrum of charged particle local density in the range from 0.5 to 200 m^-2 with the top plane, and the spectrum of local muon density in the range from 0.2 to 56 m^-2 with the bottom plane. Comparison with EAS simulations shows that the primary particle energy range which can be investigated with the SCT extends from 10^14 to 10^18 eV. This energy range includes the interval of 10^14−10^15 eV which is still insufficiently studied both in satellite and EAS experiments.
Speaker: Mr Mikhail Amelchakov (National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
• 3:30 PM
Measurement of the average electromagnetic longitudinal shower profile at the Pierre Auger Observatory 1h
In addition to the standard $X_\mathrm{max}$ and energy, the longitudinal profiles of extensive air showers contain some more interesting information. For energies above $10^{17.8}$ eV, we present the average profiles as a function of depth measured for the first time at the Pierre Auger Observatory. The profile shapes for different energy ranges are all well reproduced by a Gaisser-Hillas function with two parameters. A detailed analysis of the systematic uncertainties is done using data and a full detector simulation, and the results are compared with predictions of hadronic interaction models for different primaries.
Speaker: Francisco Diogo (LIP (Lisboa))
• 3:30 PM
MEASUREMENT OF THE ISOTOPIC COMPOSITION OF HYDROGEN AND HELIUM NUCLEI IN COSMIC RAYS WITH THE PAMELA-EXPERIMENT 1h
The cosmic-ray hydrogen and helium (1H,2H,3He,4He) isotopic composition between 100 MeV/n and 1.4 GeV/n has ­been measured with the satellite-borne experiment PAMELA. The rare isotopes 2H and 3He in cosmic rays are believed to originate mainly from the interaction of high energy protons and helium with the galactic interstellar medium. The energy spectrum of these components carries fundamental information regarding the propagation of cosmic rays in the galaxy which are competitive with those obtained from other secondary to primary measurements such as B/C. The isotopic composition was measured between 100 and 1100 MeV/n for hydrogen and between 100 and 1400 MeV/n for helium isotopes using two different detector systems over the 23rd solar minimum from July 2006 to December 2007.
Speaker: Wolfgang Menn (University of Siegen)
• 3:30 PM
Measurement of the water-Cherenkov detector response to inclined muons using an RPC hodoscope 1h
The Pierre Auger Observatory operates a hybrid detector composed of a Fluorescence Detector and a Surface Detector array. Water-Cherenkov detectors are the building blocks of the array and as such play a key role in the detection of secondary particles at the ground. A good knowledge of the detector response is paramount to lower systematic uncertainties and thus to increase the capability of the experiment in determining the muon content of the extensive air showers with a higher precision. In this work we report on a detailed study of the detector response to single muon traversals as a function of traversal geometry. A dedicated Resistive Plate Chambers (RPC) hodoscope was built and installed around one of the detectors. The hodoscope is formed by two stand-alone low gas flux segmented RPC detectors with the test water-Cherenkov detector placed in between. The segmentation of the RPC detectors is of the order of 10 cm. The hodoscope is used to trigger and select single muon events in different geometries. The signal recorded in the water-Cherenkov detector and performance estimators were studied as a function of the trajectories of the muons and compared with a dedicated simulation.
Speaker: Mr Pedro Assis (LIP)
• 3:30 PM
Measuring cosmic ray ions fluxes with AMS-02 1h
One of the key characteristic of Alpha Magnetic Spectrometer (AMS-02) is its capability to measure the relative abundances and absolute fluxes of the nuclear components of the galactic cosmic rays (CRs), from hydrogen up to iron (Z=26), in a kinetic energy range from GeV/n to TeV/n. In this contribution we discuss the methodology for the precise identification ions with AMS-02, which is relevant for the estimation of the flux ratio of secondary-to-primary CRs species, such as boro-to-carbon ratio. This is important because a precise measurement is needed to test the different propagation models and to constrain their free parameters. The raw data are first processed to extract the relevant information for the ions study, for a more efficient handling of the entire data sample. The charge identification is a combination of Z measurements from the upper and lower time of flight scintillator layers and the inner and outer silicon tracker layers (2 located at the edges and 7 layers in the inner part of the detector). The resolution and efficiency of the charge selection process is estimated by creating independent “pure” data samples for each detection layer, exploiting the available redundancy of the charge measurement. The method for the calculation of the detector acceptance for each ion species is also described. For the correct estimation of the ion fluxes we had to properly understand the fragmentation properties in case of interaction inside the detector (if the primary particle undergoes a charge change it might be wrongly identified). To tackle this problem, we developed dedicated analysis tools to study the interaction properties on Monte Carlo simulated events, that allow us to estimate the location, survival probability and fragmentation branches for each species.
Speaker: Dr Tescaro Diego (Instituto de Astrofísica de Canarias, Tenerife, Spain)
• 3:30 PM
Measuring the energy of cosmic-ray helium with the TRD of AMS-02 1h
Since May 2011 the AMS-02 experiment is installed on the ISS and is observing cosmic radiation. It consists of several state-of-the-art sub-detectors, which redundantly measure charge and energy of traversing particles. Due to the long exposure time of AMS-02 of many years the measurement of cosmic-ray energy spectra is mainly limited not by statistics, but by detector response. The measurement of momentum for protons and ions, for example, is limited by the spatial resolution and magnetic field strength of the silicon tracker. The maximum detectable rigidity (MDR, rigidity is momentum per charge) for protons is about 2 TV, for Helium below 4 TV (E<2.1 TeV/amu). In this contribution we investigate the possibility to extend the range of the energy measurement for heavy nuclei (Z>=2) with the transition radiation detector (TRD). The main purpose of the TRD of AMS-02 is the discrimination between light particles (electrons and positrons) and heavy particles (protons), and was thus designed as a threshold detector. The response function of the TRD, however, shows a steep increase in signal from the level of ionization at a Lorentz factor γ of about 500 to γ ≈ 5000, where the transition radiation signal saturates. The increase of the signal over this energy range may be used to measure the Lorentz factor for very high energy cosmic-ray ions, e.g. for helium nuclei between about 500 GeV/amu and 5 TeV/amu, well beyond the limits of the silicon tracker. From the response curve and the signal fluctuations in the TRD we derive the energy resolution of the TRD and compare it to the resolution of the silicon tracker. Furthermore, the geometric acceptance available to a TRD-based measurement can be greater by an order of magnitude compared to a standard tracker-based analysis.
Speaker: Andreas Obermeier (Rheinisch-Westfaelische Tech. Hoch. (DE))
• 3:30 PM
Measuring the Muon Production Depth in Cosmic Ray Air Showers with IceTop 1h
IceTop, the surface component of the IceCube Neutrino Observatory, detects air showers initiated by cosmic ray nuclei and gamma rays. The ground level muons are correlated with the energy and mass of the primary particle. This correlation is enhanced by resolving those muons which are produced early in the shower. The muon production depth (MPD) is reconstructed as a function of muon arrival time at ground level and distance from the shower core. This technique is most efficient when there are numerous muons that can be separated from the electromagnetic component of the shower. We use CORSIKA simulations to study the ability of IceTop to reconstruct the MPD distribution as a function of the shower's impact point, energy, and zenith angle. We explore the improvement of the measurement of the primary particle energy and mass that the reconstructed MPD can provide.
Speaker: Hershal Pandya (University of Delaware)
• 3:30 PM
Meteorological effects of muon component at the mountain muon detectors. 1h
Temperature effect of mountain muon detectors which exceeds a little that expected theoretically, was studied in this work. Meteorological effects of such detectors have their own peculiarities and practically were not investigated before. Data from multidirectional detectors YangBaJing, Moussala, Bure, Mt. Hermon, Yerevan (2000 м) were used for calculations from the created in IZMIRAN database of muon detectors mddb. To exclude model dependence the meteorological effects were studied by different methods.
Speaker: Lev Pustilnik (Israel Cosmic Ray Center, and Tel Aviv University)
• 3:30 PM
Modelling muon and neutron fluxes and spectra on the Earth's ground induced by primary cosmic rays 1h
The SecondaryCR model evaluates particle fluxes and spectra of secondary e-, e+, mu+, mu-, gammas, protons, neutrons, Cherenkov light etc. at different positions, altitudes and times in the Earth atmosphere. We developed this model of secondary cosmic rays production in the Earth's atmosphere in the previous studies. It is based on existing models evaluating particles transport in heliosphere, magnetosphere and interactions of primary cosmic rays with the atmosphere. For the evaluation at 1AU on magnetopause we use results of HelMod model. Transparency of magnetosphere was obtained by GeoMag model and finally secondary production in the Earth's magnetoshpere was simulated by Corsika package. The fluxes and spectra of neutrons and muons propagated to the ground over the globe during 22nd and 23rd solar cycle were simulated. The results are discussed in connection with neutron monitor measurements. Possibility to evaluate a neutron monitor response function from the SecondaryCR model simulations is discussed.
Speaker: Blahoslav Pastirčák (Institute of Experimental Physics SAS, Košice, Slovakia)
• 3:30 PM
Modelling the Production of Cosmogenic Radionuclides due to Galactic and Solar Cosmic Rays 1h
Cosmogenic radionuclides such as 10Be, 14C and 36Cl are a product of the interaction of high energetic primary cosmic ray particles, in particular galactic cosmic rays (GCR), with the Earth’s atmosphere. Because GCRs are modulated on their way through the interplanetary medium the GCR-induced production of these radionuclides is anti-correlated to the solar cycle. In addition, during phases of strong solar activity also solar energetic particle (SEP) events occur frequently. While the production due to GCRs can be seen as background production, in particular so-called Ground Level Enhancement (GLE) events, strong SEP events which can be detected at the Earth’s surface, may strongly contribute to the production of 10Be, 14C and 36Cl, a topic by now highly discussed in the literature. Using energy spectra of modern GLE events we will investigate the influence of 58 out of the 71 GLEs and statistically investigate the possibility to detect such events in present ice-core and tree-ring records.
Speaker: Konstantin Herbst (Christian-Albrechts-Universität zu Kiel)
• 3:30 PM
Muon Array with RPCs for Tagging Air showers (MARTA) 1h
We discuss the concept of an array with Resistive Plate Chambers (RPC) for muon detection in ultra-high energy cosmic ray (UHECR) experiments. RPC have been used in particle physics experiments due to their fast timing properties and spatial resolution. The operation of a ground array detector poses challenging demands, as the RPC must operate remotely under extreme environment, with limited power and minimal maintenance. In its baseline configuration, each MARTA unit includes one 1.5x1.2 m^2 RPC, with 64 pickup electrodes (pads). The DAQ system is based on a ASIC, allowing to readout the high number of channels with low power consumption. Data is recorded using a dual technique: single particle counting with a simple threshold on the signal from each pad and charge integration for high occupancy. The RPC, DAQ, High Voltage and monitoring systems are enclosed in an aluminum-sealed case, providing a compact and robust unit suited for outdoor environments, which can be easily deployed and connected. The RPCs developed at LIP-Coimbra are able to operate using very low gas flux, which allows running them for few years with a small gas reservoir. Several full-scale units are already installed and taking data in several locations and with different configurations, proving the viability of the MARTA concept. By shielding the detector units with enough slant mass to absorb the electromagnetic component in the air showers, a clean measurement of the muon content is allowed, a concept to be implemented in a next generation of UHECR experiments. The specificities of a MARTA unit are presented, which include particle counting with high efficiency, time resolution and spatial segmentation. The potential of the MARTA concept for muon measurements in air showers is assessed, as well as tentative methods for calibration and cross-calibrations with existing detectors.
Speaker: Raul Sarmento (LIP)
• 3:30 PM
Neutrons produced by the Earth’s crust due to Lunar and Solar tides 1h
The results presented in the report are based on the measurements of thermal neutrons flux produced by the Earth’s surface during the experiment carried out in Pamir region at the altitude of 4200 m above sea level for the period from August 1 till August 14, 1994. The neutrons in the Earth’s atmosphere are produced mainly during the interactions between the primary cosmic rays nucleons and nuclei with energy over 1 GeV with the nuclei of the elements of the atmosphere at the fission of the atmosphere’s elements nuclei. At this energy over 90% of the primary cosmic rays are protons. So we consider that the neutrons in the Earth’s atmosphere are mainly produced during the interactions between the primary cosmic rays protons with energy over 1 GeV and the nuclei of the atmosphere’s atoms. Consequently, neutrons intensity variations in the atmosphere can be associated with the variations of the protons flux. Geomagnetic cut-off rigidity for the experimental site (Moskvina meadow) is 9.2 GV, so energy threshold for the primary protons is 8.3 GeV. The period from August 1 till August 14, 1994 was quiet in terms of heliophysical and geophysical conditions. No essential variations of cosmic rays in the interplanetary space and neutrons at the ground-based neutron monitors were observed, geomagnetic conditions was quiet, no chromospheric flares on the Sun were detected. During the period from August 1 till August 9 Kp-index did not exceed 2, on August 8 for a long time it was about 0. At the end of August 9 Kp-index began to increase and reached 4 at the evening of August 10. It left at this level till August 14 and then decreased. Under quiet geomagnetic conditions and absence of chromospheric flares the intensity of the secondary cosmic rays neutrons at the Moskvina meadow was expected to stay almost constant. Although spatial anisotropy of the cosmic rays intensity leads to cosmic rays daily variations due to the Earth’s rotation, their value is small: for energy of several GeV daily variations are less than 1%. Nevertheless, according to the measurements during the period from August 1 till August 14, 1994 neutrons counting rate changed twofold and more throughout the day. Neutrons flux increased with approaching to the crossing of the local meridian by the Moon or the Sun, and then it decreased to the former level. The mentioned circumstances exclude the possibility for explanation of these variations by the known extraterrestrial factors. In the present report the authors show that the observed increases of the neutron intensity are caused by lunar and solar tides.
Speaker: Dr Nikolay Volodichev (D.V.Skobeltsyn Institute of Nuclear Physics, M.V.Lomonosov Moscow State University)
• 3:30 PM
New electronics for the surface detectors of the Pierre Auger Observatory 1h
The surface detector array of the Pierre Auger Observatory consists of 1660 water Cherenkov detectors that sample the charged particles and photons of air showers initiated by energetic cosmic rays at the ground. Each detector records data locally with timing obtained from GPS units and power from solar panels and batteries. In the framework of the planned upgrade of the Auger Observatory, new electronics has been designed for the surface detectors. The electronics upgrade includes better timing with up-to-date GPS receivers, higher sampling frequency, increased dynamic range, increased processing capability, and better calibration and monitoring systems. It will also process the data of the additional scintillator detectors planned for the upgrade. In this paper, the design of the new electronics will be presented and its performance will be discussed.
Speaker: James Beatty (Ohio State University)
• 3:30 PM
New software package of modelling of cosmic rays transport in the atmospherethe 1h
In this paper the RUSCOSMICS software package based on the GEANT4 toolkit and its possibilities in the cosmic rays are considered. Energy spectra of secondary cosmic rays particles resulting from the proton transport modeling trough the Earth atmosphere are presented. A calculations error is estimated and a comparison with experimental data is carried out. Also on the basis of the secondary cosmic rays flux intensity we investigate a contribution of different particles (protons, muons, electrons, positrons) in the ionization process in the atmosphere. The altitude profiles of ionization are presented and also a radiation absorbed dose calculation is carried out. The obtained data are compared with results of other authors.
Speaker: yury Balabin (PGI)
• 3:30 PM
New upper limit on strange quark matter flux with the PAMELA space experiment 1h
Speaker: Marco Ricci (Istituto Nazionale Fisica Nucleare Frascati (IT))
• 3:30 PM
Nuclei charge measurement with AMS-02 Silicon Tracker 1h
The Alpha Magnetic Spectrometer (AMS-02) is an astroparticle physics detector installed on the International Space Station (ISS) on May 16th 2011 during the STS-134 NASA Endeavour Shuttle mission. The purpose of the experiment is to study with unprecedented precision and statistics charged particles and nuclei in an energy range from 0.5 GeV to few TeV. The AMS-02 Tracker System accurately determines the trajectory and absolute charge (Z) of cosmic rays by multiple measurements of the coordinates and energy loss in nine layers of double sided silicon micro-strip detectors. This energy loss is proportional to the square of the particle charge thus allowing the distinction between different nuclei. The analog readout and the high dynamic range of the front end electronics allows to identify nuclear species from hydrogen up to iron and above. The charge resolution is naturally degraded by a number of detector effects that need to be correctly accounted for. In this contribution we describe the procedure that has been used to accurately calibrate the Tracker response and optimize its performances in terms of charge resolution. We will discuss the resulting analysis methods available to identify different particle species in the tracker, and present the overall measured performances.
Speaker: Mrs Stefania Vitillo (Universite de Genève)
• 3:30 PM
NuMoon: Status of ultra high energy particle searches with LOFAR 1h
The lunar askaryan technique is one of the few ways to obtain a large enough collecting area to detect ultra high energy cosmic rays and neutrinos at the highest end of the spectrum, above 10$^{21}$ eV. The flux of these particles is unknown, but if they are found they either point back to the best cosmic accelerators or may be the products of the decay of exotic particles and a step towards dark matter identification. The large collecting area is especially true for frequencies between 100-200 MHz, where the radiation is spread out over a wider angle and thus more of the lunar surface can be used for a possible detection. The NuMoon project therefore observes the Moon at these frequencies to search for nanosecond pulses. A first project with the Westerbork Synthesis Radio Telescope has placed the most stringent upper limits on the flux of ultra high energy cosmic rays and neutrinos. The next step is to observe with LOFAR, currently the most sensitive low frequency telescope. In this contribution I will present the status and plans of the project.
Speaker: Sander ter Veen (ASTRON)
• 3:30 PM
On the correlation of the angular and lateral distributions of electrons after multiple scattering allowing for energy losses 1h
We calculate analytically the correlation coefficient of the scattering angle and the lateral deflection for electrons being multiply scattered by small angles while losing energy. We show that when average losses are assumed for the bremsstrahlung process the behaviour of the correlation coefficient with electron energy is completely different from that when only the ionisation losses are assumed. We also show how the correlation changes when fluctuations in the bremsstrahlung are allowed for . Based on these results an attempt to understand the correlation for electrons in EAS is made.
Speaker: Prof. Maria Giller (University of Lodz)
• 3:30 PM
PAMELA'S MEASUREMENT OF GEOMAGNETIC CUTOFF VARIATIONS DURING SOLAR ENERGETIC PARTICLE EVENTS 1h
Data from the PAMELA satellite experiment were used to measure the geomagnetic cutoff for high-energy (above 80 MeV) protons during the solar particle events on 2006 December 13 and 14. The variations of the cutoff latitude as a function of rigidity were studied on relatively short timescales, corresponding to single spacecraft orbits (about 94 minutes). Estimated cutoff values were cross-checked with those obtained by means of a trajectory tracing approach based on dynamical empirical modeling of the Earth's magnetosphere. We find significant variations in the cutoff latitude, with a maximum suppression of about 6 degrees for 80 MeV protons during the main phase of the storm. The observed reduction in the geomagnetic shielding and its temporal evolution were compared with the changes in the magnetosphere configuration, investigating the role of IMF, solar wind and geomagnetic (Kp, Dst and Sym-H indexes) variables and their correlation with PAMELA results.
Speaker: Dr Alessandro Bruno (Department of Physics, University of Bari, I-70126 Bari, Italy)
• 3:30 PM
PAMELA'S MEASUREMENT OF GEOMAGNETICALLY TRAPPED AND ALBEDO PROTONS 1h
Data from the PAMELA satellite experiment were used to perform a detailed measurement of under-cutoff protons at low Earth orbit. On the basis of a trajectory tracing approach using a realistic description of the magnetosphere, protons were classified into geomagnetically trapped and albedo. The former includes stably-trapped protons in the South Atlantic Anomaly, which were analyzed in the framework of the adiabatic theory, investigating energy spectra, spatial and angular distributions. PAMELA data were compared with other spacecraft measurements and with predictions of recent theoretical models. The albedo protons were classified into quasi-trapped, concentrating in the magnetic equatorial region, and un-trapped, spreading over all latitudes and including both short-lived (precipitating) and long-lived (pseudo-trapped) components. Features of the penumbra region around the geomagnetic cutoff were investigated in detail. PAMELA results significantly improve the characterization of the high energy proton populations in near Earth orbits.
Speaker: Dr Alessandro Bruno (Department of Physics, University of Bari, I-70126 Bari, Italy)
• 3:30 PM
Parallelization schemes for AIRES's Monte Carlo 1h
In this work we introduce different parallelization schemes implemented in the AIRES (AIR-shower Extended Simulations) software, in order to perform simulations, without thinning algorithm, in HPC clusters. The AIRES's particle stack was modified to define a new structure allowing its parallelization using MPI library. Adopting this new structure, three different parallelization tactics were implemented according to how particles are transferred between the working nodes: 1) Transfer based on the amount of particles stored in the stacks, 2) Transfer based on the energy of particles stored in the stacks 3) Transfer based on the energy of particles stored in the stacks, with decisions according the characteristics of the particle's nucleus type. As part of this paper will be present a comparison of the obtained results between the most performant parallelized version of AIRES and original version of AIRES, considering longitudinal and lateral profiles of vertical showers induced by Fe primaries of $10^{16.75} eV$. Towards the end of this work we will include an analysis of performance results of each parallelization tactic evaluated by different simulations of vertical showers whose energies are between $10^{15.75} eV$ and $10^{18.75} eV$.
Speaker: Leonardo Dominguez (Departamento de Computación de Alta Prestación - Comisión Nacional de Energía Atómica)
• 3:30 PM
Performance and Operational Status of Muon Detectors in the Telescope Array Experiment 1h
Measurement of shower particles using scintillators at ground level, with different absorber thicknesses, enables detailed studies of the Telescope Array experiment’s energy scale and of hadronic interaction models. We designed and constructed two types of such detectors. In this report, we present their performance and operational status.
Speaker: Toshiyuki Nonaka (Institute for Cosmic Ray Research, University of Tokyo)
• 3:30 PM
Predicted CALET Measurements of Heavy and Ultra-Heavy Cosmic Ray Nuclei 1h
The CALorimetric Electron Telescope (CALET) is a Japanese-Italian-US astroparticle observatory expected to be installed on the ISS in 2015. The main calorimeter (CAL) on CALET is comprised from top to bottom of a charge detector (CHD) with two crossed layers of scintillator paddles, an imaging calorimeter (IMC) with planes of scintillating fibers interleaved with tungsten sheets, and a total absorption calorimeter (TASC) made of lead tungstate logs. The main science objectives of CAL are to measure the combined cosmic ray electron and positron spectrum to 20 TeV, gamma rays to 10 TeV, and nuclei $1 \leq Z \leq 40$ to 1,000 TeV. In this paper we present the expected numbers and energy spectra of heavy ($26 \le Z < 30$) and ultra-heavy (UH) ($30 \le Z \le 40$) Cosmic Ray (CR) nuclei that CAL will measure in a planned 5 year mission in the full detector geometry accounting for geomagnetic screening and interactions in the CHD. We will also present the numbers of UH CR nuclei that it will measure using the expanded acceptance permitted utilizing the earth’s geomagnetic field to screen for events above $\sim 600$ MeV/nucleon. Above this threshold the UH charges can be resolved using the CHD with a trajectory correction from the top half of the IMC without the need for energy measurement in the TASC.
Speaker: Dr Brian Flint Rauch (NASA-Natl. Aeronaut. & Space Admin. (US))
• 3:30 PM
PROTON AND LIGHT ION INTERACTIONS IN COSMIC RAY EXPERIMENT ”STRATOSPHERE” IN COMPARISON WITH RECENT COLLIDER RESULTS 1h
Estimation of physical properties of exited fireball from complex final pattern of produced particles is key challenge in nucleus-nucleus collisions at high energies. Effective way to better understanding and interpretation of results consists in analyses of interaction of smaller systems, created in proton-proton or in proton-nucleus collisions.On the basis of such approach interactions of cosmic ray light nuclei and protons with different targets have been studied in the experiment “Stratosphere” at energies above10 TeV in Lab system[1]. Results have shown that in rare events, produced by alpha-particles and light nuclei, transverse momentum spectra of secondary γ-quantain soft region (up to 2 GeV/c) have exponential character with large values of inverse slope of the distributions: TA ~ 0,8 GeV/c. On the contrary, in the proton interactions the slope is essentially smaller Tp~ 0,2 GeV/c. For charged secondary particles the high order intermittency analyses have again demonstrated the large difference between events produced by protons and nuclei. So, the essential system size dependence in forward production dynamics has been obtained on limited statistics. Similar events were observed by JASSE and Concorde cosmic ray collaborations. New instanton-induced interpretation has been suggested for explanation. Obtained result is an important issue to be tested at collider experiments. The launch of the Large Hadron Collider (LHC) open broad new possibilities for high energy physics at TeV scale. Previous RHIC exploration on soft physics at midrapidity [2] were developed in the work of the ALICE collaboration [3]. In the very forward region the new experiments have been performed at LHC forward detector – LHCf. In proton-proton collisions at 900 GeV and at 7 TeV transverse momentum distribution for inclusive neutral pions has been measured in 2010 [4] and in p-Pb collisions at 5.02 TeV in 2013 [5]. All proton induced data (with antiproton–proton collisions at 630 GeV from UA 7 experiment)have shown that there is the weak dependence of average value of the neutral pion PT distribution from CMS energy [6]. The exponential fit for the spectra [4, 5] well enough coincide with the correspond estimation from our Stratosphere experiment. In the proposal [7] a new forward particle production experiment PHENIX-RHICf has suggested, in which p-p, proton-Nitrogen, and Nitrogen-Nitrogen, Fe-Nitrogen, - as a future options, - are considered. Realization of the direct collider measurements of light ion collisions will be very important both for frontier problems of high energy heavy ion physics and foractualhigh energy cosmic ray problems. Reference 1. A.KhArgynova et al., Proc. of 27-th ICRC, p.1477-1480, Hamburg, 2001. 2. S. Esumi - Soft physics at Phenix, ProgrTheorExpPhys, 2015, 03A104 3. B. Abelev et al., ALICE collaboration, pp and Pb-Pb, HAL arXiv: hal-01104892, 19 Jan, 2015. 4. O. Adriani et al., - LHCf collaboration, arXiv: 1205.4578. 5. O. Adriani et al., - LHCf collaboration, arXiv: 1403.7845. 6. M.Hiroaki - for LHCf collaboration, ICRC 2013, Rio de Janeiro. 7. Y. Ito et al., - proposal – forward particle production at RHIC, arViv: 1401.1004, 1409.4860.
Speaker: Yernar Tautayev (Institute of Physics and Technology, Almaty, Kazakhstan)
• 3:30 PM
R&D of EAS radio detection in China 1h
In order to study ultra-high-energy cosmic-ray (UHECR) sources, we need not only to know their direction, energy and chemical composition, but also large statistics of experimental data, which requires that the detector should have a large effective area and a high duty cycle. Radio antennas present some attractive aspects in this perspective, with very low unit costs, easiness of deployment over large areas and 100% duty cycle; they are therefore suitable for detecting UHECRs. In the Tianshan Mountain range (Xinjiang Autonomous Region, China), a radio-interferometer named 21 CMA was deployed, which aims at studying the epoch of reionization by detecting the hydrogen 21 cm radiation. On this site, the Sino-French cooperation experiment TREND (Tianshan Radio Experiment for Neutrino Detection) has performed autonomous detection and identification of EAS with a stand-alone and self-triggered array of 50 radio antennas. This inspires us to investigate the polarization characteristics of the radio signal with a hybrid array of 21 scintillators and 35 antennas measuring the x, y and z components of the electric field emitted by air showers. This hybrid setup is expected to provide a quantitative evaluation of the EAS identification & background rejection of the radio technique. If successful, this experiment would open the door for stand-alone, giant radio arrays dedicated to the study of high energy cosmic particles, such as the GRAND project.
Speaker: Dr Zhaoyang Feng (IHEP,CAS)
• 3:30 PM
Results from the Telescope Array from data collected in hybrid-trigger mode 1h
The Telescope Array is a hybrid detector which consists of a surface detector (SD) and three air fluorescence detector sites surrounding the SD array. Hybrid data collection began in May 2008, with independent triggering of the two detector systems. Since October 2010, the SD array has been triggered with an external trigger from the fluorescence detectors (called a "hybrid-trigger") designed to collect SD information for events at primary energies where the standard SD trigger is inefficient. In this paper, we introduce our hybrid-trigger performance and report on analysis results using this trigger. 4 years of data will go into this analysis.
Speaker: Hisao Tokuno (UTokyo)
• 3:30 PM
Search for energy dependent patterns in the arrival directions of cosmic rays at the Pierre Auger Observatory 1h
Energy-dependent patterns in the arrival directions of cosmic rays could arise from deflections in galactic and extragalactic magnetic fields. We report on searches for such patterns in the data of the surface detector of the Pierre Auger Observatory at energies above E = 5 EeV in regions within approximately 15° of the arrival directions of events with energy E > 60 EeV. No significant patterns are found with this analysis which can be used to constrain parameters in propagation scenarios.
Speaker: Dr Tobias Winchen (Bergische Universität Wuppertal)
• 3:30 PM
Search for isotropic microwave radiation from electron beam in the atmosphere 1h
We report a search for 12.5 GHz microwave radiation from electron beams in the atmosphere. Ultrahigh-energy cosmic rays (UHECRs) are observed indirectly through extensive air showers (EASs) by particle detectors on the ground or fluorescence detectors using a remote sensing method. If isotropic radiation of microwave from EAS is detected, it can be used for future observation of the UHECR based on a remote sensing method just like fluorescence detector with 100 % duty cycle like particle detectors. Week attenuation in the atmosphere is another advantage to measure microwave radiation. To study microwave radiation from EAS, we used Electron Light Source (ELS) located at the Telescope Array Observatory in Utah, USA. The ELS emitted electron beams vertically into the atmosphere. Energy of the electron in the beam is 40 MeV which is similar to that in the EAS. About 600 million electrons are contained in a beam, which is equivalent to the shower maximum of an air shower created from 10 to 17 eV cosmic ray. The beam is triangular pulse of which the base is 20 ns. Commercial equipment for the satellite television are utilized for the microwave detection system. 1.2 m diameter parabola with 12.5 GHz receiver which measures vertical and horizontal polarizations is fixed on a concrete pad which is located at 80 m away from the electron beam. About 1500 beam shots were observed and no microwave signal has been detected. In this contribution we will report details of this detector, its calibration and obtained upper-limit on the intensity of isotropic radiation of 12.5 GHz microwave.
Speaker: Prof. Tokonatsu Yamamoto (Konan Univeristy)
• 3:30 PM
Search for UHE Photons with the Telescope Array Hybrid Detector 1h
In order to understand sources of ultra high energy cosmic rays, we search for ultra high energy photons with the Telescope Array experiment. The Telescope Array is a hybrid detector consisting of an array of scintillation detectors, which measure the lateral profile of air showers, and fluorescence detectors, which measure the longitudinal profile of air showers. This information is used to search for photon-like events. We will report on the analysis method, and the result of a photon search using five years of TA data.
Speaker: Katsuya Yamazaki (University of Tokyo)
• 3:30 PM
Search for Ultra-relativistic Magnetic Monopoles with the Pierre Auger Observatory 1h
Ultra-relativistic magnetic monopoles, possibly a relic of phase transitions in the early universe, would deposit an amount of energy comparable to UHECRs in their passage through the atmosphere, producing highly distinctive air shower profiles. We have performed a search for ultra-relativistic magnetic monopoles in the sample of air showers with profiles measured by the Fluorescence Detector of the Pierre Auger Observatory. No candidate was found to satisfy our selection criteria and we establish upper limits on the isotropic flux of ultra-relativistic magnetic monopoles - the first from an UHECR detector - improving over previous results by up to an order of magnitude.
Speaker: TOSHIHIRO FUJII (University of Chicago, University of Tokyo)
• 3:30 PM
Seasonal variations in the intensity of muon bundles detected at the ground level 1h
Experimental data accumulated in a 3-year long series of measurements (from May 2012 to April 2015) of cosmic ray muon bundles with the coordinate-tracking detector DECOR are analyzed. It has been found that the measured rate of the events exhibits clear seasonal variations, repeated every year of observations. The amplitude of the first annual harmonic of the event rate has been estimated as (5.7 +/- 0.1) % with the maximal intensity in January, and the minimal one in July. Thus, the difference between the average intensity of muon bundles recorded in winter and in summer exceeds 10 %. Taking into account that the mean energy of muons registered in the bundles is of the order of several tens GeV, the observed difference cannot be described in frame of a well-known mechanism of the formation of the temperature effect due to decays of low energy particles in the atmosphere, which is typical for single muons detected at the ground level. An alternative explanation related with changes of the shape of the lateral distribution function of EAS muons in the atmosphere with a variable temperature profile is discussed.
Speaker: Prof. Rostislav Kokoulin (National Research Nuclear University MEPhI (Moscow Engineering Physics Institute))
• 3:30 PM
Sidereal anisotropy of Galactic cosmic ray observed by the Tibet Air Shower experiment and the IceCube experiment 1h
The IceCube experiment presented in 2012 the declination dependence of the first and second harmonic coefficients of the sidereal cosmic-ray anisotropy at 20 TeV and 400 TeV. In this presentation, we calculate the coefficients for the comic ray data observed by the Tibet ASgamma experiment at median energies of 12 TeV and 300 TeV during a period between November 1999 and May 2010. By using these coefficients combined, we analyze the sidereal anisotropy for the first time based on the two-hemisphere observations by the IceCube and the Tibet ASgamma experiments.
Speaker: Prof. Kazuoki Munakata (Shinshu University, Nagano, Japan)
• 3:30 PM
Simulations for CALET Energy Calibration Confirmed Using CERN-SPS Beam Tests 1h
CALorimetric Electron Telescope (CALET) is a detector for the precise measurement of cosmic ray electrons, gamma-rays and nuclei on the International Space Station. CALET has an imaging and a thick calorimeter, which provide excellent energy resolution and particle identification. For the on-orbit calibration, we plan to use the minimum ionizing particles of cosmic rays such as protons and helium nuclei. We have carried out MC simulations to develop an algorithm of penetrating event selection by event reconstruction and to estimate the on-orbit event rate for the calibration. We have also carried out the beam tests at the CERN-SPS to assess the detector performance and the validity of our MC simulation and calibration methods. In this paper, we present the calibration methods and expected detector performance with beam test results.
Speaker: Yosui Akaike (University of Tokyo (JP))
• 3:30 PM
Status and Prospects of the Auger Engineering Radio Array 1h
The Auger Engineering Radio Array (AERA) is a low-energy extension of the Pierre Auger Observatory. It is used to detect radio emission from extensive air showers in the 30 - 80 MHz frequency band. A focus of interest is the dependence of the radio emission on shower parameters such as the energy and the distance to the shower maximum. After three phases of deployment, AERA now consists of 153 autonomous radio stations with different spacings, covering an area of about 17 km$^2$. The size, station spacings, and geographic location at the same site or near other Auger low-energy detector extensions, are all targeted at cosmic ray energies above $10^{17}$ eV. The array allows us to explore different technical schemes to measure the radio emission as well as to cross calibrate our measurements with the established baseline detectors of the Auger Observatory. We will report on the most recent technological developments and experimental results obtained with AERA.
Speaker: Mr Johannes Schulz (Department of Astrophysics/IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands)
• 3:30 PM
Study of UHECR Composition Using Telescope Array's Middle Drum Detector and Surface Array in Hybrid Mode 1h
The seven year Telescope Array (TA) Middle Drum hybrid composition measurement shows agreement between Ultra-High Energy Cosmic Ray (UHECR) data and a light composition obtained with QGSJetII-03 or QGSJet-01c models. The data are incompatible with a pure iron composition, for all models examined, for energies log10(E/eV)>18.2. This is consistent with previous TA results. This analysis is presented using an updated version of the pattern recognition analysis (PRA) technique developed by TA.
Speaker: Mr Jon Paul Lundquist (Telescope Array Project)
• 3:30 PM
Studying Cosmic Ray Composition with IceTop using Muon and Electromagnetic Lateral Distributions 1h
In this contribution we will consider the methods at our disposal to estimate the mass of primary cosmic rays on an event-by-event basis using IceTop, the surface component of the IceCube detector at the geographical South Pole. We reconstruct the events using two lateral distribution functions, one for the muon component and one for the electrons and gamma rays. This results in a few parameters that are sensitive to primary mass: the muon density at large lateral distances and the steepness of the lateral distribution of the electromagnetic component of the air shower. This approach is complementary to the technique already used in IceCube, whereby one can get a mass sensitive parameter using the air shower size in IceTop together with several observables from the deep portion of the detector. Most importantly, this approach allows the study of composition-dependent anisotropy, since the zenith angle range is not constrained by the requirement of detecting the air shower in the deep detector.
Speaker: Javier Gonzalez (Bartol Research Institute, Univ Delaware)
• 3:30 PM
Taiwan Astroparticle Radiowave Observatory for Geo-synchrotron Emissions (TAROGE) 1h
TAROGE is an antenna array on the high mountains of Taiwan’s east coast for the detection of ultra-high energy cosmic ray (UHECR) in energy above 10^19 eV. The antennas will point toward the ocean to detect radiowave signals emitted by the UHECR-induced air-shower as a result of its interaction with the geomagnetic field. Looking down from the coastal mountain, the effective area is enhanced by collecting both direct-emission as well as the ocean-reflected signals. This instrument also provides the capability of detecting Earth-skimming tau-neutrino through its subsequent tau-decay induced shower. A prototype station with 12 log-periodic dipole array antennas for 110-300MHz was successfully built at 1000 m elevation near Heping township, Taiwan in July 2014 to prove the detection concept. It has been operating smoothly for radio survey and optimization of instrumental parameters. We plan to install another station on a higher mountain in summer 2015. In this report, we discuss the design of TAROGE, performance of the prototype station, expected sensitivity, and future prospect.
Speaker: Prof. Jiwoo Nam (LeCosPA and Department of Physics, National Taiwan University)
• 3:30 PM
Telescope Array measurement of UHECR composition from stereoscopic fluorescence detection 1h
The chemical composition of ultra-high-energy cosmic rays (UHECRs) affects the observable distribution of air-shower $X_{\rm max}$ values, the atmospheric slant depth at which the number of secondary shower particles reaches its maximum. The observed $X_{\rm max}$ distributions at various primary UHECR energies can be compared with the distributions predicted by detailed detector simulations for any assumed composition and high-energy hadronic interaction model. In this poster, we present measurements of $X_{\rm max}$ by the Telescope Array (TA) fluorescence detectors with stereoscopic shower reconstruction. We find that for all hadronic models considered, the data collected since TA operation began in 2007 is consistent with a chiefly light UHECR composition.
Speakers: Dr Thomas Stroman (University of Utah), Dr Yuichiro Tameda (Institute for Cosmic Ray Research, University of Tokyo)
• 3:30 PM
Testing for uniformity of UHECR arrival directions 1h
Arrival directions of ultra-high energy cosmic rays (UHECRs) exhibit mainly isotropic distribution with a hint of small deviations in particular energy bins. In this paper available UHECR data are tested for circular uniformity of arrival directions using methods developed in directional statistics.
Speaker: Anatoly Ivanov (Shafer Institute for Cosmophysical Research & Aeronomy)
• 3:30 PM
The AMIGA Muon Counters of the Pierre Auger Observatory: Performance and Studies of the Lateral Distribution Function 1h
The AMIGA enhancement (Auger Muons and Infill for the Ground Array) of the Pierre Auger Observatory consists of a 23.5 km$^2$ infill area where air shower particles are sampled by water-Cherenkov detectors at the surface and by 30 m$^2$ scintillation counters buried 2.3 m underground. The Engineering Array of AMIGA, completed since February 2015, includes 37 scintillator modules (290 m$^2$) in a hexagonal layout. In this work, the muon counting performance of the scintillation detectors is analysed over the first 22 months of operation. A parametrisation of the detector counting resolution and the lateral trigger probability are presented. Finally, preliminary results on the observed muon lateral distribution function (LDF) are discussed.
Speaker: Dr Brian Wundheiler (Instituto de Tecnologías en Detección y Astropartículas)
• 3:30 PM
The Cosmic Ray Nuclear Composition Measurement Performance of the Non-Imaging CHErenkov Array (NICHE) 1h
The Non-Imaging CHErenkov Array (NICHE) will eventually measure the flux and nuclear composition of cosmic rays from below $10^{15}$ eV to $10^{18}$ eV by using measurements of the amplitude and time-spread of the air-shower Cherenkov signal to achieve a robust event-by-event measurement of XMax and energy. NICHE will have sufficient area and angular acceptance to have significant overlap with TA/ TALE, within which NICHE is located, in both fluorescence and Cherenkov measurements allowing for energy cross-calibration. In order to quantify NICHE’s ability to measure the cosmic ray nuclear composition, two different cosmic ray composition models, one based on the poly-gonato model of J. Hörandel (AstroPart 19, 2003) and the other based on the H4a model of T. Gaisser (Astropart 35, 2012), using simulated $X_{Max}$ distributions of the composite composition as a function of energy. These composition distributions were then unfolded into individual components via an analysis technique that included NICHE’s simulated $X_{Max}$ and energy resolution performance as well as the effects of finite event statistics as a function of measured energy. In this talk, NICHE’s ability to distinguish between these two CR composition evolution models and determine the individual components as a function of energy will be presented.
Speaker: John Krizmanic (USRA/CRESST/NASA/GSFC)
• 3:30 PM
The distribution of shower longitudinal profile widths as measured by Telescope Array in stereo mode 1h
Observing UHECR air showers in stereo mode provides a precise measurement of their longitudinal profiles. The Gaisser-Hillas function fits air shower profiles well on average. The range of shower widths can be sensitive to details of average inelasticity and multiplicity in the early part of the shower. Such a measurement can then also be used to constrain the interaction models used in simulating UHECRs. This work can augment the conventional stereo composition measurement. The distribution of the Gaisser-Hillas function FWHM value will be made in bins of energy, matching the bins used in the stereo composition analysis. These distribution will then be compared to Monte Carlo simulations using standard interaction models (QGSJet, Sibyll, EPOS).
Speaker: Douglas Bergman (University of Utah)
• 3:30 PM
The effect of geomagnetic field on radio signal patterns from cosmic ray air showers 1h
Abstract: Different type of mechanisms are involved in generation and propagation of radio signals from cosmic ray air showers. The geomagnetic origin is one of such mechanisms which is very important especially in low frequency band studies. Based on CORSIKA and CoREAS we investigate the influence of earth magnetic field parameter on filtered peak radio amplitude patterns in 32–64 MHz frequency band using a specifically designed computer code. Simulated showers are from Proton and Iron primary particles with 10^17 eV initial energy. It is found that radio signal patterns are heavily dependent on the Earth magnetic field values so that they change fundamentally as we go from southern to northern hemisphere. We have chosen Pierre Auger Observatory in South and Tehran in North hemisphere for comparison purposes. Analyzing these patterns can clearly show the importance and influence of the Earth magnetic field parameter on the radio signal patterns from cosmic ray air showers.
Speaker: Mr Mohammad Sabouhi (Department of Physics , Semnan University, P.O. Box 35196-45399, Semnan, Iran)
• 3:30 PM
The Guane Array of the LAGO Project 1h
The Space Weather program of the Latin American Giant Observatory (LAGO) is based on the installation of single or small arrays of water-Cherenkov detectors (WCD) spanned across Latin America. The Guane Array is one of the LAGO detection network nodes and it is located in the city of Bucaramanga, Colombia, at $986$ m a.s.l. The array is composed of three autonomous LAGO WCD installed at the vertices of a $105$ m side equilateral triangle. Each WCD is locally operated by a low power consumption single board computer and the first steps of the data analysis are done on board of the detector to reduce data transfer, as a test for the operation of WCD in remote sites. The array operates with two complementary analysis modes: the counting mode, a single particle technique implementation at each individual detector, and the shower mode, which allows the offline identification of space­time correlated signals over the array. In this work it will be presented the capabilities, characterization and first results of the Guane Array.
Speaker: Christian Sarmiento-Cano (Universidad Industrial de Santander)
• 3:30 PM
The Influence of Magnetic Fields on UHECR Propagation from Virgo A 1h
Active galactic nuclei (AGN) are considered as one of the most appropriate sources of cosmic rays with energy exceeding $~\sim 10^{18}~$eV. Virgo$~$A (M87 or NGC 4486) is the second closest to the Milky Way active galaxy. According to existing estimations it can be a prominent source of ultra high energy cosmic rays (UHECR). However not many events have been registered in the sky region near Virgo$~$A, possibly due to magnetic field influence. In present work we check UHECR events from recent sets of data (AUGER, Telescope Array etc.) for possibility of their origination in this AGN. We carried out the simulation of UHECR motion from Virgo$~$A taking into account their deflections in galactic (GMF) as well as extragalactic (EGMF) magnetic fields according to several latest models. The maps of expected UHECR arrival directions have been obtained as a result. It has been found following: 1)$~$UHECR deflection caused by EGMF is comparable with GMF one, moreover the influence of EGMF sometimes is dominating; 2)$~$effect of EGMF demonstrates obvious asymmetry in final distribution of expected UHECR arrival directions; 3)$~$the results of simulation depend on chosen GMF model and are still open for further discussion.
Speaker: Oleh Kobzar (Institute of Nuclear Physics, Polish Academy of Sciences)
• 3:30 PM
The lunar Askaryan technique, which involves searching for Askaryan radio pulses from particle cascades in the outer layers of the Moon, is a method for using the lunar surface as an extremely large detector of ultra-high-energy particles. The high time resolution required to detect these pulses, which have a duration of around a nanosecond, puts this technique in a regime quite different from other forms of radio astronomy, with a unique set of associated technical challenges which have been addressed in a series of experiments by various groups. Implementing the methods and techniques developed by these groups for detecting lunar Askaryan pulses will be important for a future experiment with the Square Kilometre Array (SKA), which is expected to have sufficient sensitivity to allow the first positive detection using this technique. Key issues include correction for ionospheric dispersion, beamforming, efficient triggering, and the exclusion of spurious events from radio-frequency interference. We review the progress in each of these areas, and consider the further progress expected for future application with the SKA.
Speaker: Justin Bray (University of Manchester)
• 3:30 PM
The multi-sources M. C. collision generator GHOST for C R simulations at LHC energies 1h
GHOST (1) is .an extension of HDPM (Hybrid dual parton model) originally implemented in CORSIKA(2). It reproduces the pseudo-rapidity charged distribution for NSD events measured by LHCb, CMS and TOTEM …up to √s = 8TeV. At this energy, two pairs of normal generators are centered symmetrically, respectively at small rapidity 1.05 and mid rapidity 4.1, with respective widths 0.95 and 1.8 units of rapidity. Together with NSD and inelastic components, we detail the diffractive component (single and double). A more important rise of central rapidity density suggests also an enhancement of the total multiplicity. The semi-inclusive data is used to evaluate the consequences of the violation of the KNO scaling. The fluctuations of multiplicity are governed by the Negative binomial distribution and the opportunity of an asymptotic form of the energy dependent functions introduced by UA5 is investigated at UHE.; the results in limited pseudo rapidity intervals are used to evaluate a partial scaling , adjust the parameters of GHOST and describe the semi-inclusive pseudo rapidity distributions expected on a large range of rapidity. The validity of the relation between transverse momentum Pt and multiplicity at very high energy is also considered. Those improvements have consequences in the simulation of EAS suggesting a maximum depth at higher altitude and a muon content more important than with previous models at least for $E_{o}\geq 2.10^{16}$ eV. Comparisons are performed in addition with unexpected signals observed in EAS and in Gamma ray families in the energy range √s = 2-14 TeV(up to $10^{17}$eV for EAS). (1) Proceedings ISVHECRI CERN 2014 (to be published in EPJ) (2) The simulation program CORSIKA, J.Knapp, D.Heck J.N. Capdevielle, G. Schatz, T.Thouw,
Speaker: Jean-Noël CAPDEVIELLE (CNRS)
• 3:30 PM
The muon detector prototype AMD for the determination of the muon content in UHECRs 1h
Precise measurements of the muon content of extensive air showers are essential for the identification of the chemical composition of ultra-high-energy cosmic rays. We therefore propose a new scintillator detector prototype, the Aachen Muon Detector (AMD). It can complement existing ground arrays composed of e.g. water Cherenkov detector stations. The detector consists of 64 scintillator tiles read out by silicon photomultipliers (SiPM) which are located in a steel housing which could be placed beneath the existing detector stations. SiPMs promise a photon detection efficiency which outperforms current photomultiplier tubes. In combination with their compact package, low cost per light sensor and a moderate bias voltage ($<100$ volts) a modular and robust design can be achieved. We present the current status of the AMD prototype, including first characterization measurements of the scintillator tiles and first promising simulation studies. We use a detailed detector simulation based on Geant4 to determine the efficiency of the AMD detector to reconstruct the simulated muon number in air showers.
Speaker: Christine Peters (RWTH Aachen University)
• 3:30 PM
The NICHE Array: status and plans 1h
The Non-Imaging CHErenkov Array (NICHE) will be a low energy extension to Telescope Array and TALE using an array of closely spaced (~200 m) light collectors covering an area of ~2 square km. It will be deployed in the field of view of TALE and will overlap it in energy range. Showers with energies 1-100 PeV will be reconstructed using both the Cherenkov light Lateral Distribution and the Cherenkov time Width Lateral DIstribution. These two methods will allow shower energy and Xmax to be determined. A prototype of the array, called j-NICHE, is currently being built and deployed. The design and plans for the full array are presented along with a plan to deploy the first 25 counters to get a true Cherenkov hybrid air shower measurement.
Speaker: Douglas Bergman (University of Utah)
• 3:30 PM
The north-south asymmetry change during solar magnetic field reversal measured by PAMELA. 1h
The north-south asymmetry of galactic cosmic rays has been measured in the PAMELA experiment during the time period 2010-2014. Inside this period the solar magnetic field has been flipped. This gave the opportunity to follow the variation of the asymmetry effect. The variation of high energy cosmic rays ratio for particles arriving from Nord and South has been measured with aid of PAMELA instrument calorimeter. The solar magnetic field polarity flip has been taking place during part of this time interval. It was obtained that the value of this ratio has changed during the same time. So the obtained result confirm the conclusion about connection of Nord-South particle flux asymmetry with solar magnetic field.
Speaker: Dr Alexander Karelin (NRNU MEPhI)
• 3:30 PM
The Sites of the Latin American Giant Observatory 1h
The Latin American Giant Observatory (LAGO) is an extended cosmic ray observatory, which consists in a wide network of water Cherenkov detectors (WCDs) located in nine different countries. The geographic distribution of the LAGO sites, with different altitudes and geomagnetic rigidity cut-offs, combined with the new electronic system for control, atmospheric sensing and data acquisition on board of each detector, allow the realization of multiple and variated astrophysics, space physics and atmospherics physics studies at regional scale. This work will describe the LAGO sites and the capabilities of the LAGO detection network spanned across Latin America.
Speaker: Dr Alberto Carramiñana Alonso (INAOE)
• 3:30 PM
The study on the potential of muon measurements on the determination of the cosmic ray composition using a new fast simulation technique 1h
In this work we study the energy evolution of the number of muons in air showers. Motivated by future plans for UHECR experiments, the analysis developed here focus on how the evolution of the moments of the shower observables distributions (Xmax and the number of muons at ground) can be used to assess the validity of a mass composition scenario, surpassing the current uncertainties on the shower description. The cosmic ray composition is an essential ingredient for an astrophysical interpretation of the data. However, the inference of composition from air shower measurements is limited by the theoretical uncertainties on the high energy hadronic interactions. Statistical analyses using the energy evolution of different observables, like the moments of the Xmax and of the moments of the number of muons distributions, can provide an efficient method to surpass these limitations imposed by the uncertainties in hadronic interaction models and provide more reliable information about the cosmic ray abundance. A new technique is presented here to generate a large set of simulated shower observables minimizing computer processing time. Fast algorithms to simulate the longitudinal development of the shower (i.e. CONEX) are long available. However, the number of muons is measured along the lateral development of the shower, which implies that tridimensional simulations are needed (i.e. CORSIKA). This paper presents a parameterization of the main shower characteristics that can be used to simulate the muon lateral distribution on ground using fast simulation algorithms. The parametrization was used in CONEX to produce a large library of showers. Xmax and the lateral distribution of muons were simulated. These showers were used to explore and discriminate among hypothetic astrophysical scenarios of mass composition.
Speaker: Mario Pimenta (LIP Laboratorio de Instrumentaco e Fisica Experimental de Particulas)
• 3:30 PM
The TUS orbital detector simulation 1h
The TUS space experiment is aimed to study energy spectrum and arrival distribution of UHECR at energy range above 1020 eV by the measurement of the EAS fluorescent radiation in atmosphere. The TUS mission is planned for launch at the end of 2015 at the dedicated “Lomonosov” satellite. TUSSIM program package was developed to simulate the TUS detector performance including the Fresnel mirror optical parameters, the light concentrator of the photo detector and the front end and trigger electronics. In order to investigate the detector response, we employ the software package ESAF of JEM-EUSO experiment for the fluorescent radiation of EAS. Trigger efficiency is crucially dependent on the background level that is changed from ~0.2*106 to ~15*106 ph/(m2*microsec*sr) at moonless and full moon nights respectively. The TUSSIM algorithms is described and the expected TUS statistics is presented for 5 years of data collection from 500 km solar-sinchronized orbit taking into account the background light intensity change during the space flight.
Speaker: Dr Leonid Tkachev (JINR, Dubna)
• 3:30 PM
Time asymmetries in the Surface Detector signals of the Pierre Auger Observatory. 1h
The asymmetry in the risetime of signals in Auger surface detector stations with respect to the direction of an incoming air shower is a source of information on shower development. The asymmetry is due to a combination of the longitudinal evolution of the shower and geometrical effects related to the angles of incidence of the particles into the detectors. The magnitude of the effect depends upon the zenith angle and state of development of the shower and thus provides a novel observable sensitive to the mass composition of cosmic rays above $4 {\times} 10^{18}$ eV. By comparing measurements with predictions from shower simulations, we find for both of our adopted models of hadronic physics (QGSJETII-04 and EPOS LHC) that the mean cosmic ray mass increases with energy, as has been inferred from other studies. However the absolute values of the mass are dependent on the shower model and on the range of distance from the shower core selected. Thus the method has uncovered further deficiencies in our understanding of shower modelling that ought to be resolved before the mass composition can be inferred from $(\sec\theta)_{max}$.
• 3:30 PM
Detection of transition radiation from neutrino-induced showers escaping a dense medium is a promising technique which might be employed in future generations of ultra-high energy neutrino detectors. Using the well-known Zas-Halzen-Stanev (ZHS) Monte Carlo simulation, we have computed the electric field created by showers crossing a dense medium-air interface. Our calculations show that transition radiation is sizeable in a wide solid angle range with full coherence up to $\sim$ 1 GHz. These properties could make possible the design of large aperture detectors with low signal threshold. The work reported here represents a stepping stone for future dedicated investigations of particular experimental setups.
Speaker: Pavel Motloch (University of Chicago)
• 3:30 PM
Ultra-High Energy Air Shower Simulation without Thinning in CORSIKA 1h
Interpretation of EAS measurements strongly depends on detailed air shower simulations. One of the big limitations is the calculation time of Monte-Carlo programs like CORSIKA at very high energies. Thinning algorithm has been introduced in the past to reduce the computation time and disk space of the output at the price of the loss of small scale structures in simulated air showers. Thanks to the newly developed parallelization scheme and special tools to study multiple thinning level for a given shower on a limited disk space, it is now possible to compare thinned and unthinned simulation of a single shower to quantify these losses. Preliminary results will be presented together with the details of the last release of CORSIKA.
Speaker: Dr Tanguy Pierog (KIT)
• 3:30 PM
Understanding the anisotropy of cosmic rays at TeV and PeV energies 1h
The anisotropy in cosmic-ray arrival directions in the TeV-PeV energy range shows both large and small-scale structures. While the large-scale anisotropy may arise from diffusive propagation of cosmic rays, the origin of the small-scale structures remains unclear. We perform three-dimensional Monte-Carlo test-particle simulations, in which the particles propagate in both magnetostatic and electromagnetic turbulence derived from a three-dimensional isotropic power spectrum. However, in contrast to earlier studies, we do not use a backtracking method for the computation of the particle trajectories, and hence anisotropy must build up from a large-scale isotropic (or dipole) boundary condition. It has been recently argued that the turbulent magnetic field itself generates the small-scale structures of the anisotropy if a global cosmic-ray dipole moment is present. Our code is well suited to test that hypothesis. We also investigate the impact of a finite phase velocity of interstellar turbulence.
Speaker: Martin Pohl (DESY)
• 3:30 PM
Zenithal dependence of muon intensity 1h
The zenital dependence of muon intensity which reaches the earth's surface is well known as proportional to cos^n (theta). Generally, for practical purposes and simplicity in calculations, n is taken as 2. However, compilations of measurements show dependence on the geographical location of the experiments as well as the muons energy range. Since analytical solutions appear to be increasingly less necessary because of the higher accessibility to low cost computational power, accurate and precise determination of the value of the exponent n, under different conditions, can be useful in the necessary calculations to estimate signals and backgrounds, either for terrestrial and underground experiments. In this work we discuss a method for measuring n using a simple muon telescope and the results obtained for measurements taken at Campinas (SP), Brazil (22^o 54' W, -41^o 03', 854 m asl) and at Fermilab - Batavia (IL), United States (41.8319∘𝑁, 88.2572∘ 𝑊, 220 m). After validation of the method, we intend to extend the measurements for more geographic locations due to the simplicity of the method, and thus collect more values ​​of n that currently exist in compilations of general data on cosmic rays.
Speaker: Ms Monica Nunes (UNICAMP)
• 3:30 PM 4:30 PM
Poster 1 DM and NU Amazon Foyer Terrace

Amazon Foyer Terrace

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 3:30 PM
A dual-PMT optical module (D-Egg) for IceCube-Gen2 1h
The next upgrade of IceCube Neutrino observatory (IceCube-Gen2) enhances the detection capability of neutrinos with a few hundred TeV energies or greater by the increased instrumented volume in the glacier ice. Enhancement of the optical sensor performance in detecting ultra-violet photons can be a key factor for IceCube-Gen2 to achieve a higher sensitivity as more Cherenkov lights are expected in the short wavelengths. We have developed an optical module housing two 8" photo-multiplies (PMTs) in an UV transparent oval shaped glass. The two high-QE PMTs are installed in a way facing both up and down so that the resultant angular acceptance is more uniform. This uniformity of optical acceptance further improves the downward-going event detection and background veto efficiency compared to the current IceCube optical sensors. In addition, the improvements on UV transmittance of the housing glass and the inner gel lead to an improvement of the photon detection efficiency by a factor of four at wavelengths shorter than 340 nm. Here, the initial performance of the first prototype module of D-EGG is reported. We also present simulation studies of the IceCube-Gen2 performance with the new dual-PMT modules.
Speaker: Lu Lu (Chiba University)
• 3:30 PM
A fussy revisitation of antiprotons as a tool for Dark Matter searches 1h
Antiprotons are regarded as a powerful probe for Dark Matter (DM) indirect detection and indeed current data from PAMELA have been shown to lead to stringent constraints. However, in order to exploit their constraining/discovery power properly and especially in anticipation of the exquisite accuracy of upcoming data from AMS, great attention must be put into effects (linked to their propagation in the Galaxy) which may be perceived as subleasing but actually prove to be quite relevant. We revisit the computation of the astrophysical background and of the DM antiproton fluxes fully including the effects of: diffusive reacceleration, energy losses including tertiary component and solar modulation (in a force field approximation). We show that their inclusion can somewhat modify the current bounds, even at large DM masses, and that a wrong interpretation of the data may arise if they are not taken into account. The numerical results for the astrophysical background are provided in terms of fit functions; the results for Dark Matter are incorporated in the new release of the PPPC4DMID.
Speaker: Mathieu Boudaud (LAPTh Annecy France)
• 3:30 PM
A method of electromagnetic shower identification by using isolated bars with the DAMPE BGO calorimeter 1h
A method is proposed for electron/hadron discrimination for 3D imaging BGO calorimeter DAMPE (DArk Matter Particle Explorer) experiment. The technique uses isolated bars which are extracted by comparing to their nearby bars in the same layer. We find that the energy distribution and location of isolated bars are highly sensitive to the type of interaction of incident particle. Based on the Monte Carlo investigation of the characters of isolated bars, we demonstrate a particle identification algorithm that can efficiently distinguish electromagnetic shower and hadronic shower. The method is verified by using beam test data taken at CERN PS and SpS.
Speaker: Chi WANG (USTC)
• 3:30 PM
A Precision Optical Calibration Module for IceCube-Gen2 1h
A next generation of IceCube is under design targeting the Precision IceCube Next Generation Upgrade (PINGU) for the neutrino mass ordering and an extended array for astrophysical neutrino sources. A new level of precision is needed in order guarantee improved performances respect IceCube. A better calibration system will enable a better understanding of the ice and will therefore significantly reduce systematic effects. We present a new instrument called the Precision Optical Calibration Module (POCAM). By keeping the outer topology identical to that of the IceCube Digital Optical Module (DOM), cost effective construction and deployment is ensured. The design of the POCAM is based on the principle of an inverted integrating sphere. An appropriately placed LED in combination with a diffusing layer on the inside of the sphere results in an isotropic light emission from the apertures in the spherical housing. The output of the LED is monitored in-situ to high precision, it therefore ensures control over the output from the apertures. The POCAM has been simulated and tested in the framework of Geant4. A prototype POCAM is under construction. We will report about the status of the POCAM R&D.
Speaker: Kai Krings (Technische Universität München, Physik-Department)
• 3:30 PM
Acoustic positioning system for KM3NeT 1h
KM3NeT is the next generation neutrino telescope in the Mediterranean Sea employing the technique of Cherenkov photon detection. The Acoustic Positioning System (APS) is a mandatory sub-system of KM3NeT that must provide the position of the telescope’s mechanical structures, in a geo-referenced coordinate system. The APS is important for a safe and accurate deployment of the mechanical structures and, for science sake, for precise reconstruction of neutrino-induced events. The KM3NeT APS is composed of three main sub-systems: 1) an array of acoustic receivers (hydrophones and piezos) rigidly connected to the telescope mechanical structures; 2) a Long Base-Line (LBL) of acoustic transmitters (beacons) and receivers, anchored on the seabed in known positions; 3) a farm of PCs for the acoustic data analysis, on-shore. On shore, the positions of the acoustic receivers are calculated by measuring the ToF (Time Of Flight) of the LBL beacons’ signals on the acoustic receivers, thus determining, via multi-lateration, the position of the acoustic receivers with respect to the geo-referenced LBL. The synchronized and syntonized electronics and the data transmission/acquisition allows for calculating the latencies of the whole data acquisition chain with accuracy better than 100 ns. The APS, in combination with compass and tilt, pressure, current and sound velocity data, is expected to measure the positions of the digital optical modules in the deep sea with accuracy of about 10 cm. Since data are continuously transmitted to shore and distributed to the local data acquisition network at the shore station, acoustic data are available also for Earth and Sea science users. The KM3NeT APS is also an excellent tool to study the feasibility of a neutrino acoustic detector and a possible correlation between acoustic and optical signals.
Speaker: Piera Sapienza (INFN)
• 3:30 PM
Boosting the boost: the effect of tidal stripping on the subhalo luminosity 1h
In the paradigm of ΛCDM, structures form hierarchically, implying that large structures contain smaller substructures. These so-called subhalos can enhance the dark matter annihilation signal that one expects to see from a given host halo, the effect of which is called the boost factor. In the literature this boost factor is typically calculated assuming a density profile for the substructure, or analogously a concentration-mass relation, corresponding to that of field halos. However, since subhalos accreted in a gravitational potential of their host loose mass through tidal stripping and dynamical friction, they have a quite characteristic density profile, different from that of the field halos of the same mass. In this work we attempt to quantify the effect of tidal stripping on the boost factor. We find that the boost factor increases by a factor few for host halos ranging from sub-galaxy to cluster masses.
Speaker: Richard Bartels (University of Amsterdam)
• 3:30 PM
Calibration, performances and tests of the first detection unit of the KM3NeT neutrino telescope 1h
KM3NeT is the next generation neutrino telescope being installed in the Mediterranean Sea. The first detection unit of the telescope is ready for installation in the deep Mediterranean Sea in the summer of 2015. Eighteen digital optical modules have been mounted on a vertical string for the detection of the Cherenkov light emitted by muons induced by up-going neutrinos. This paper reports on the integration and calibration of the optical modules and of the full detection unit, as well as the future installation in the deep sea and the on-shore operation. The additional information carried out by the new type of photo-detection units when comparing to the old generation of optical modules is also discussed.
Speaker: Alexandre Creusot (Universite de Paris VII (FR))
• 3:30 PM
Confronting recent AMS-02 positron fraction and Fermi-LAT Extragalactic $\gamma$-ray Background measurements with gravitino dark matter 1h
The positron fraction measured by the space-based detectors PAMELA, {\it Fermi}-LAT and AMS-02 presents anomalous behaviour as energy increase. In particular AMS-02 observations provide compelling evidence for a new source of positrons and electrons. Its origin is unknown, it can be non-exotic (e.g. pulsars), be dark matter (DM) or maybe a mixture. We test the gravitino of bilinear R-parity violating supersymmetric models as this source. As the gravitino is a spin 3/2 particle, it offers particular decay channels, $W^{\pm}l^{\mp}_i$, $Z\nu_i$, and $H\nu_i$. We compute the electron, positron and $\gamma$-ray\ fluxes produced by each gravitino decay channel as it would be detected at the Earth's position. Combining the flux from the different decay modes we can fit AMS-02 measurements of the positron fraction, as well as the electron and positron fluxes, with a gravitino dark matter mass in the range $1-2$ TeV and lifetime of $\sim 1.0-0.8\times 10^{26}$ s. The high statistics measurement of electron and positron fluxes, and the flattening in the behaviour of the positron fraction recently found by AMS-02 allow us to determine that the preferred gravitino decaying mode by the fit is $W^{\pm}\tau^{\mp}$, unlike previous analyses. Then we study the viability of these scenarios through their implication in $\gamma$-ray observations. We set limits on the gravitino lifetime using the Extragalactic $\gamma$-ray Background recently reported by the {\it Fermi}-LAT Collaboration and a state-of-the-art model of its known contributors. These limits exclude the gravitino parameter space which provides an acceptable explanation of the AMS-02 data. Therefore, we conclude that the gravitino of bilinear R-parity violating models is ruled out as the unique primary source of electrons and positrons needed to explain the rise in the positron fraction.
Speaker: German Gomez-Vargas (Pontifical Catholic University of Chile)
• 3:30 PM
Design studies for a neutrino telescope based on optical fiber hydrophones 1h
Acoustic detection may provide way to observe ultra-high energy cosmic neutrinos, i.e. energies above 10^18 eV, and their extra-galactic sources [1, 2]. The expected flux of cosmic neutrinos with ultra-high energy is low, so that large scale neutrino telescopes are needed for this emerging field of astroparticle physics. Using the acoustic signals induced by a neutrino interaction in water (or ice) has the advantage that sound can travel for many kilometers with only small attenuation in the relevant frequency range. A hydrophone network that uses the sea as a detection medium may therefore be the solution to detect the ultra-high energy neutrinos. It has been advocated that fiber optic hydrophone technology is a promising means to establish a sensitive, cost-effective and large scale sensor network [3]. In this technology several hydrophone sensors are integrated on a optical fiber. The sensors transform the acoustic pressure in to strain in the fiber. Subsequently, this strain causes a wavelength shift of the light that travels through the fiber and that is sensed using an interrogator. Hydrophones based on optical fibers, provide the required sensitivity to detect the small signals from neutrinos. At the same time, optical fibers form a cost-effective and straightforward way for the installation of a large scale network. In this talk we discuss the system design for a fiber optic hydrophone network. We provide a flow-down from the scientific objectives to the instrument requirements. This has led to the design of a new and improved hydrophone sensor. Measurements to characterize the sensor and to show its performance will be presented. In addition the performance of the interrogator is discussed and measurements are shown, leading to an overall performance prediction of the technology. [1] G. A. Askaryan. Acoustic recording of neutrinos. Zemlia i Vselennaia, 1:13–16, 1979. [2] J. G. Learned. Acoustic radiation by charged atomic particles in liquids: An analysis. Phys. Rev. D, 19:3293–3307, June 1979. [3] E. J. Buis et al. Fibre laser hydrophones for cosmic ray particle detection. Journal of Instrumentation, 9(03):C03051, 2014.
Speaker: Dr Ernst-Jan Buis (TNO)
• 3:30 PM
Development of an automatic test system for the PMTs used in the BGO ECAL of DAMPE 1h
An automatic system has been developed for the batch test of the photomultiplier tubes (PMTs) in the BGO electromagnetic calorimeter (ECAL) of Dark Matter Particle Explorer (DAMPE). There are 616 PMTs (Hamamatsu R5610A-01) used in the BGO ECAL, which are critical for the realization of high dynamic readout and high precision measurement of the scintillation light from BGO crystals. In order to cover the large dynamic range of energy measurement of DAMPE, signals are read out from three dynodes of the PMTs. The charge ratios of the dynodes are of paramount importance to the energy reconstruction of high energy incident particles so that all the PMTs must be tested and calibrated. In addition, considering of the high reliability and quality requirements as a space-borne experiment, over 800 PMTs were tested during the mass production and screening procedure both for the Qualification Model and the Flight Model. Therefore, a light-emitting diode (LED) based system was designed to test the performance of PMTs automatically.
The test system is composed of a signal generator, a LED driver module, a dark box, and a readout system which consists of front end electronics (FEE) board, data acquisition (DAQ) board and a data acquisition software based on Labwindows/CVI. An arbitrary waveform generator drives the LED source for illuminating 22 PMTs through optical fibers in one dark box. Then 66 dynode signals are read out by a FEE board, sent to DAQ module, stored in the computer and finally analyzed with a root program. As two dark boxes can be controlled simultaneously by the readout system, it takes about 30 minutes to test 44 PMTs per time, which reduces the workload greatly and guarantees the project schedule. The details about this system and the test results are presented in this paper.
Speaker: Jianing Dong (USTC)
• 3:30 PM
Development of new data acquisition system at Super-Kamiokande for nearby supernova bursts 1h
Super-Kamiokande (SK) is a 50-kiloton water Cherenkov detector. It is one of the most sensitive neutrino detectors and can be used for supernova observations by detecting supernova burst neutrinos. Recently, it is reported that Betelgeuse (640ly) is shrinking 15% in 15 years (C. H. Townes et al., 2009). Although this report does not immediately imply the supernova explosion of Beteleuse, it triggered the possibility of the nearby supernova. The simulation study based on the Livermore model predicts the 30MHz neutrino event during a burst from a supernova within a few hundred light years. The current SK data acquisition (DAQ) system can record only the first 20% of these events and a large fraction of the data afterwards will be lost. To overcome this problem, we developed a new DAQ system to record the number of hit PMTs. This system enabled us to store high-rate events and study a time profile of the number of neutrinos emitted at the supernova. This new system uses the number of hits from existing frontend electronics modules as inputs and is synchronized with them. Therefore, we can easily correlate the data from the new system and the existing system. The data is transferred to the computers via Ethernet with SiTCP. High frequency detailed data are stored for 1 minute in the 4GB DDR2 memory and they are transferred when a supernova burst is detected. The summarized data are constantly read out by the computers and stored in the disk for a week. We will monitor the event rate by this data and pre-scale the data of the existing DAQ system. The controlled pre-scaling enables us to measure the energy spectrum. Now the system is under commissioning. We will report the status of the operation.
Speaker: Asato Orii (University of Tokyo)
• 3:30 PM
Development of the time domain simulation of impulsive radio signals for ARAcalTA 1h
Speaker: Keiichi Mase (Chiba University)
• 3:30 PM
Development of TRBs for Silicon Tracker Detector of DAMPE satellite 1h
The Silicon Tungsten Tracker (STK) is a detector of the DAMPE satellite to measure the incidence direction of high energy cosmic ray. It consists of 6 layers of silicon micro-strip detectors interleaved with Tungsten converter plates. The entire STK contains 73,728 readout channels totally and can be read out according to external average 50 Hz trig. It’s a great challenge for space mission that all data acquisition (DAQ) works of detector signal digitization, data process and transfer are finished in 3 milliseconds dead time. In order to meet above requirements, 8 identical Tracker Readout Boards (TRB) are developed to control and read the front Application Specific Integrated Circuits (ASIC) signals. 8 TRBs work simultaneously according to every trig. In each TRB, there are 2 Field Programmable Gate Arrays (FPGA), 48 serial ADCs to process front 144 ASICs. A SRAM is also adopted in each TRB for data buffer. LVDS and RS422 are used for scientific data and telemetry communication with payload DAQ. Benefiting from the FPGA’s rich resources and feature of work in parallel, data process includes pedestal subtraction, common noise subtraction, cluster finding and data compressing is realized inside two FPGAs. The TRB readout electronics of hardware and software for STK will be introduced in this poster.
Speaker: zhang fei (IHEP)
• 3:30 PM
Fiber laser design and measurements for fiber optical hydrophones in their application for ultra-high energy neutrino detection 1h
The detection of ultra-high energy neutrinos with energies above 10^18 eV requires a neutrino telescope that is at least an order of magnitude larger than what has been achieved today [1]. A potential technology for a large scale neutrino telescope, which is sensitive enough to detect the low thermo-acoustic signals induced by the cosmic rays in water, is offered by fiber optical hydrophones [2]. Optical fibers form a natural way to create a distributed sensing system in which several transducers are attached to a single fiber. The detection system in this case will consist of several transducers, erbium doped fiber lasers and an interferometric interrogator. Next to the advantage of having multiple sensors on a single fiber, this technology has a low power consumption and no electromagnetic interference with other read-out electronics. Maybe even more important, fiber optics technology provides a cost-effective and straightforward way to implement a large number of hydrophones. In this paper we will show the results of investigations on one of the key components of the technology, i.e. the optical fiber laser. For the targeted application in a fiber optical hydrophone, the fiber laser technology requires a development beyond the present state of the art. In this light, design studies on in the various laser types and laser geometries have been carried out and trade-offs are made, supported with lab measurements. Moreover the multiplexing and cross-talk between several lasers on a single fiber have been investigated. Finally, the integration of the fiber laser in to the acoustical transducer will be shown. [1] E.Waxman. Neutrino astrophysics: A new tool for exploring the universe. *Science*, 315(5808):63-65, 2007. [2] E. J. Buis et al. Fibre laser hydrophones for cosmic ray particle detection. *Journal of Instrumentation*, 9(03):C03051, 2014.
Speaker: Vincent Baas (TNO)
• 3:30 PM
Generation-2 IceCube Digital Optical Module and DAQ 1h
With recent exciting observations of astrophysical TeV- to PeV-energy neutrinos and new competitive measurements of GeV-energy atmospheric neutrino oscillations in the IceCube neutrino observatory at the South Pole, the design of a second generation Antarctic neutrino observatory, IceCube-Gen2, is underway. The design calls for two new instrumented volumes, one a denser in-fill array to extend the sensitivity of IceCube to energies low enough to gain sensitivity to the neutrino mass hierarchy, and one approximately ten times larger than IceCube, about 10 cubic kilometers in extent, to improve the sensitivity of IceCube to high energy astrophysical neutrinos and their sources. The detectors will share many common hardware elements and will leverage the successful hardware and software of the first generation experiment. They will feature updated data acquisition electronics using commercially available components and taking advantage of advances in embedded computing power. We will look at the status of the modernized in-ice Digital Optical Module (DOM) and the supporting surface electronics and data acquisition components.
Speaker: Michael DuVernois (University of Wisconsin)
• 3:30 PM
GSL in Unified DE-DM Dominated LQC 1h
Thermodynamic study is the common approach to understand dark energy (DE) and dark matter (DM) riddle. The respective approach is still not comparatively matured in loop quantum cosmology (LQC). Our present work follows the study of the status of generalized second law (GSL) in unified DE-DM dominated LQC scenario.
Speaker: Dr Julie Saikia (Pub Kamrup College)
• 3:30 PM
Isospin violating dark matter in Stückelberg portal scenarios 1h
In this work we study the phenomenological aspects of Stückelberg portals where the mediator between the Standard Model and the dark matter (DM) is a massive Z' boson. Those scenarios are well motivated by certain string theory constructions and naturally lead to i sospin violating interactions of DM particles with nuclei. We show that within this construction the relations between the DM coupling to neutrons and protons for both, spin-independent (fn/fp) and spin-dependent (an/ap) interactions are generically different from plus and minus 1 (i.e. different couplings to protons and neutrons) leading to a potentially measurable distinction from other popular portals. Finally, we perform a scan over all the parameters of the model and we incorporate bounds from searches for dijet and dilepton resonances at the LHC as well as LUX bounds on the elastic scattering of DM off nucleons to determine the experimentally allowed values of fn/fp and an/ap. We also obtain the phenomenological consequences of this kind of constructions for direct detection and indirect detection signals.
Speaker: Victor Martin-Lozano (IFT-UAM/CSIC)
• 3:30 PM
Moon shadow observation with the ANTARES neutrino telescope 1h
The ANTARES detector is the largest neutrino telescope currently in operation in the North Hemisphere. One of the main goals of the ANTARES telescope is the search for point-like neutrino sources. For this reason both the pointing accuracy and the angular resolution of the detector are important and a reliable way to evaluate these performances is needed. One possibility to measure the angular resolution and the pointing accuracy is to analyse the shadow of the Moon, i.e. the deficit in the atmospheric muon flux in the direction of the Moon induced by absorption of cosmic rays. Analysing the data taken between 2007 and 2012, the Moon shadow is detected with about 3σ significance in the ANTARES data. The first measurement of the ANTARES angular resolution and absolute pointing for atmospheric muons using a celestial calibration source is obtained. The presented results confirm the good pointing performance of the detector as well as the predicted angular resolution.
Speaker: Matteo Sanguineti (INFN Genova - Università di Genova)
• 3:30 PM
Multi-PMT optical modules for IceCube-Gen2 1h
Following the first observation of astrophysical high-energy neutrinos by IceCube, planning for a next-generation neutrino detector at the South Pole is under way, which will expand IceCube's sensitivity both towards high and low neutrino energies. In parallel to upgrading the proven IceCube design, new optical sensor concepts are explored which have the potential to further significantly enhance the performance of IceCube-GenTwo. One concept pursued is the multi-PMT optical module which, in contrast to the "conventional" layout with a single 10" photomultiplier (PMT), features 24 3" PMTs inside a pressure vessel. This design results in several advantages such as increased effective area, improved angular acceptance and directional sensitivity. The layout is based on the proven design of the KM3NeT optical module which is now being adapted and enhanced for the use in the deep ice. We present the current state of the hardware developments as well as first simulations investigating the impact of multi-PMT modules on detector performance.
Speaker: Lew Classen (University Erlangen-Nuremberg)
• 3:30 PM
Performance of the Read-out Electronics of the Qualification Model of DAMPE BGO Calorimeter in Environmental Tests and CERN Beam Experiment 1h
The DAMPE (DArk Matter Particle Explorer) is a scientific satellite mainly aimed at indirectly searching for dark matter in space. One critical sub-detector of the DAMPE payload is an electromagnetic calorimeter, which consists of 308 BGO (Bismuth Germanate Oxid) crystal bars and 616 PMTs (photomultiplier tubes), for precisely measuring the energy of cosmic rays from 5 GeV to 10 TeV. The calorimeter, with 1848 readout channels and a dynamic range of 2×10^5 for each crystal bar, is equipped with a complex readout system which contains 16 front-end electronics boards (FEE) with a total power consumption of 26 W. The qualification model of the BGO calorimeter, as well as its readout electronics, has been constructed and passed a series of environmental tests, such as EMC (Electromagnetic Compatibility) test, vibration test, thermal cycling test and thermal-vacuum test. The readout electronics system performed well and each electronics channel achieved a dynamic range of 0 to 12.5 pC with a resolution better than 3 fC and nonlinearity less than 1%. Test results showed that it could adapt to the harsh space environments. Later in the fall of 2014, an accelerator beam experiment was successfully carried out at CERN with PS and SPS facilities, which suggested that the design specifications of the BGO calorimeter and its readout electronics were achieved.
Speaker: Dr Deliang Zhang (University of Science and Technology of China)
• 3:30 PM
Performances and main results of the KM3NeT prototypes 1h
The KM3NeT collaboration aims to build a km3-scale neutrino telescope in the Mediterranean Sea. The first phase of construction comprises the deep-sea and onshore infrastructures at the KM3NeT-It (100 km offshore Capo Passero, Italy) and KM3NeT-Fr (40 km offshore Toulon, France) sites and the installation of 31+7 detection units. For the next step (KM3NeT 2.0) completion of two detectors are planned as extension of the detectors realized during the first phase of construction: ARCA for high energies (E > TeV) in Italy and ORCA for low energies (GeV range) in France. A prototype digital optical module made of 31'' PMTs was deployed in April 2013 inside the ANTARES neutrino telescope. This prototype, attached to an ANTARES string, is operating since its installation. It validated the multi-PMT technology and demonstrated the capability to identify muons with a single optical module searching for local time coincidences between PMTs inside the optical module. A prototype detection unit made of three optical modules was installed at the KM3NeT-It site. It was deployed in May 2014; it is active and taking data. More than 700 hours of data have been recorded and analyzed. The experience achieved with this prototype detection unit validates the submarine deployment procedures, the mechanics and the electronic of the apparatus, the data taking and analysis procedures. Through the study of $~^{40}$K decay in sea water and dedicated data taking periods with flashing LED beacons, it is possible to calibrate in time the detector with nanosecond stability. A dedicated algorithm has been developed to select atmospheric muons and reconstruct their zenith angle with a resolution of about 8 degrees. An excellent agreement is found when comparing the detected signal from muons with Monte Carlo simulations. The performance and results of the two prototypes will be presented.
Speaker: Alexandre Creusot (Universite de Paris VII (FR))
• 3:30 PM
PINGU camera 1h
IceCube is the world’s largest neutrino telescope located at the geographic South Pole, that utilizes more than 5000 optical sensors to observe Cherenkov light from neutrino interactions. A hot water drill was used to melt holes in the ultra-pure Antarctic ice, in which strings of optical sensors were deployed at a depth of 1500m to 2500m. The recent observation of high energy neutrinos consistent with astrophysical origin, as well as measurements of neutrino oscillation parameters and world-leading searches for dark matter, have demonstrated the great potential of this detector type. Extensions to the IceCube detector are now being considered. Ice properties, including the refrozen hole ice, have emerged as major source of uncertainty for event reconstruction. A camera system integrated with optical sensor modules could be tremendously beneficial in order to better understand ice properties and interpret calibration measurements. In this presentation we will describe the merits of the camera system and present a preliminary design. The preliminary design foresees a system of high resolution cameras located inside the DOM, to study the refrozen and surrounding ice. The impact of the camera system on geometry calibration, sensor location and orientation will be discussed.
Speakers: Carsten Rott (Sungkyunkwan University), Debanjan Bose (Sungkyunkwan University)
• 3:30 PM
Progress on the development of a wavelength-shifting optical module 1h
We report on the development of a photon sensor sensitive to single photons that employs wavelength-shifting and light-guiding techniques to maximize the collection area and to minimize the dark noise rate. The sensor is tailored towards applications in ice-Cherenkov neutrino detectors using inert and cold, low-radioactivity and UV transparent ice as a detection medium, such as IceCube-Gen2 or MICA. The goal is to decrease the energy threshold as well as to increase the energy resolution and the vetoing capability of the neutrino telescope, when compared to a setup with optical sensors similar to those used in IceCube. The detector captures photons with wavelengths between 250$\,$nm to 400$\,$nm. These photons are re-emitted with wavelenghts above 400$\,$nm by a wavelength shifter coating applied to a 90$\,$mm diameter polymer tube which guides the light towards a small-diameter PMT via total internal reflection. By scaling the results from smaller laboratory prototypes, the total efficiency of the proposed detector for a Cherenkov spectrum is estimated to exceed that of a standard IceCube optical module by a factor of 2.7. The status of the prototype development and performance of its main components as well as the potential for future IceCube extensions will be discussed.
Speaker: Dustin Hebecker (Humboldt Universität zu Berlin / DESY)
• 3:30 PM
Self Consistent Simulation of Dark Matter Annihilation And Background 1h
Future space based experiments such as CALET and DAMPE will measure the electron and positron cosmic-ray spectrum with better energy resolution and up to higher energy, making detection of small features in the spectrum, which might originate from Dark Matter annihilation or decay in the galactic halo, possible. For precise prediction of these features, the numerical cosmic ray propagation code GALPROP is used, and was extended to calculate the flux at Earth from different Dark Matter scenarios with any given injection spectrum. The results from GALPROP for both the cosmic-ray background spectrum and the component from Dark Matter annihilation are strongly dependent on the bin size in energy used in the calculation, due to energy loss playing a major role in the propagation of electrons. A modification to partly compensate the influence of the discretization of the energy shifted particles has been implemented in the code. The effect of this improvement is demonstrated with examples of the expected spectra for the cosmic ray background in combination with several Dark Matter candidates calculated at different energy binning. http://www.crlab.wise.sci.waseda.ac.jp/eng/wp-content/uploads/downloads/2015/03/icrc.png This figure shows the background electron flux is subjected to a shift in power law index due to finite energy bin size, as shown by the difference between the results for calculation with a bin size of 4% (magneta line), and 30% (orange dots)of the energy. In the result for the modified code (green dots) the change is compensated, giving results matching the finer energy binning. The AMS-02 results and a possible Dark Matter Contribution(electron+positron channel,Mass of DM=400GeV, Boost Factor=130) are shown in maroon and grey respectively.
Speaker: Saptashwa Bhattacharyya (Waseda University)
• 3:30 PM
Simulation studies of the expected proton rejection capabilities of CALET 1h
The CALorimetric Electron Telescope (CALET) is a Japanese led international space mission by JAXA (Japanese AeroSpace Agency) in collaboration with the Italian Space Agency (ASI) and NASA. The instrument will be launched to the International Space Station in 2015. The major scientific goals for CALET are to measure the flux of cosmic-ray electrons (including positrons) from 1 GeV to 20 TeV, gamma rays to 10 TeV and nuclei with Z=1 to 40 up to 1,000 TeV. These measurements are essential to search for dark matter signatures, investigate the mechanism of cosmic-ray acceleration and propagation in the Galaxy and discover possible astrophysical sources of high-energy electrons nearby the Earth. The instrument consists of two layers of segmented plastic scintillators for the cosmic-ray charge identification, a 3 radiation length thick tungsten-scintillating fiber imaging calorimeter and a 27 radiation length thick lead-tungstate calorimeter. Protons are the largest source of background for the high-energy electron observation. As the ratio of protons to electrons increases at higher energies, a proton rejection power better than $10^5$ is necessary to measure the electron spectrum with a proton contamination below a few percent in the TeV energy region. In this work, a Monte Carlo based study of the proton rejection capability CALET can achieve from GeV to TeV energies is presented. Both standard analysis based on consecutive selection criteria and multivariate analysis are applied to simulated samples of signal and background events. Finally, the resulting accuracy and signal-to-background ratio expected in the electron spectrum measurement are assessed.
Speaker: Roberta Sparvoli
• 3:30 PM
Site Characterization and Detector Development for the Greenland Neutrino Observatory 1h
The PeV neutrinos discovered by IceCube are of astrophysical origin, and their progenitors could be any of several source classes, including active galactic nuclei, gamma-ray bursts, or pulsars. Such high-energy accelerators would produce neutrinos up to hundreds of PeV, which motivates the development of neutrino telescopes with the sensitivity, energy resolution, and pointing resolution required to distinguish among models of the IceCube neutrinos as well as cosmogenic neutrinos. Radio detection of Askaryan radiation from neutrino showers in ice is well-suited to the detection of the highest energy neutrinos, with degree-scale pointing resolution and the ability to build sparse arrays, but the energy threshold of current experiments is currently set by the temperature of the ice. The uncorrelated thermal noise can be averaged away by combining the signals from several antennas in a phased array. We report here on a June 2015 trip to Summit Station in Greenland for testing a phased array of dipoles, including the sensitivity of the array and background measurements of the site. We also discuss prospects for the Greenland Neutrino Observatory.
Speaker: Stephanie Wissel (UCLA)
• 3:30 PM
Software framework and reconstruction software of the DAMPE gamma-ray telescope 1h
An overview is given for the offline software framework and reconstruction software of the DAMPE (DArk Matter Particle Explorer) gamma-ray telescope. DAMPE is one of the five satellite missions in the framework of the Strategic Pioneer Research Program in Space Science of the Chinese Academy of Sciences, with a launch date scheduled for the fall 2015. The telescope consists of silicon-tungsten tracker-converter, comprising 6 layers of double-sided silicon-strip detectors, interleaved with 3 layers of tungsten converters, BGO calorimeter, and plastic scintillator, serving as anti-coincidence detector, and a layer of neutron detector in the bottom of the calorimeter. DAMPE analysis and reconstruction software is implemented based on the custom-made software framework, where the core software is written in C++, while the management part is done in Python. We take advantage of the boost-python libraries, whereby the bridge between the core and management part is done, allowing us to fully exploit the computational power of modern CPUs, while keeping the framework flexible and easy to deploy. The building blocks of the framework are the algorithms, which are stacked together and configured in the the job-option files. The geometry of the detector is implemented in the GDML format, through the direct conversion from the CAD drawings of the detector to the geant4-compatible format. The data flow is handled by the dedicated input-output service, based on ROOT. The simulation algorithms are implemented with the Geant4 tool kit. In the heart of the reconstruction software lies the pattern recognition for the initial track finding, which is refined further by the track filtering algorithm, based on the adaptation of Kalman technique. The software has been extensively put on test during the beam test campaigns at CERN, in 2014-2015 years, proving its sustainability to a wide range of data-processing challenges, encountered in a particle-physics experiment.
Speaker: Dr Andrii Tykhonov (Universite de Geneve (CH))
• 3:30 PM
Space qualification of the Silicon Tungsten Tracker of DAMPE 1h
Silicon Tungsten Tracker (STK) is one of the key payloads of Dark Matter Particle Explorer (DAMPE), which is planned to be launched at the end of 2015. In order to verify the design of STK, an Engineering Qualification Model (EQM) of STK was developed in 2014 and qualified for several space environmental tests, including vibration test, shock test, thermal vacuum test, thermal balance test and thermal cycling test. All the test results demonstrate the high reliability and good performance of STK, which also trigger the following production of flight model (FM).
Speaker: Wenxi Peng (IHEP)
• 3:30 PM
Status and prospects for the Askaryan Radio Array (ARA) cosmogenic neutrino detector 1h
The Askaryan Radio Array (ARA) is an ultra-high energy >100 PeV cosmic neutrino detector which is in phased construction near the South Pole. ARA searches for radio Cherenkov-like emission from particle cascades induced by neutrino interactions in the ice using radio frequency antennas (~150-800MHz) deployed at a design depth of 200m in the Antarctic ice. A prototype ARA Testbed station was deployed at ~30m depth in the 2010-2011 season and the first three full ARA stations were deployed in the 2011-2012 and 2012-2013 seasons. We present the status of the array and plans for the near-term construction of a full ARA-37 detector with profound discovery potential for most models of cosmogenic neutrinos from 100 PeV to 100 EeV in energy.
Speaker: Michael DuVernois (University of Wisconsin)
• 3:30 PM
The Calibration Units of the KM3NeT Neutrino Telescope 1h
KM3NeT is a network of deep-sea neutrino telescopes to be deployed in the Mediterranean Sea, that will perform neutrino astronomy and oscillation studies.  It consists of three-dimensional arrays of thousands of optical modules that detect the Cherenkov light induced by charged particles resulting from the interaction of a neutrino with the surrounding medium. The performance of the neutrino telescope relies on the precise timing and positioning calibration of the detector elements. The exact location of optical modules (which is affected by sea currents) can be monitored through an acoustic positioning system, while external light sources are used to achieve the required sub-nanosecond time resolution and to measure water optical properties. Other environmental conditions which may affect light and sound transmission, such as water temperature, pressure and salinity, must also be continuously monitored. For these purposes, KM3NeT foresees the deployment of several dedicated Calibration Units (CUs), whose base will host the detector calibration devices (Laser beacon, acoustic emitter and hydrophone). A few of these CUs will additionally be equipped with an Instrumentation Unit with a semi-autonomous and recoverable inductive line supporting the environmental monitoring instruments. This contribution describes the technical design and construction of the first Calibration Unit, to be deployed on the French site as part of KM3NeT Phase 1, as well as the purpose and characteristics of the different instruments that it will support.
Speaker: Veronique Van Elewyck (Universite Paris Diderot)
• 3:30 PM
The Dark Box instrument for fast automatic testing of the photomultipliers for KM3NeT 1h
Since the early days of experimental particles physics photomultipliers have played an important role in detector design. Also in astroparticle physics research, photomultipliers are largely used, in particular in experiments employing the technique of the detection of Cherenkov photons. Currently, the KM3NeT Collaboration is building a water Cherenkov neutrino telescope in the Mediterranean Sea based on the next generation optical modules with multiple low price 3-inch photomultiplier tubes. In its final layout, the KM3NeT neutrino telescope will host several hundred thousand photomultipliers, which must be tested and calibrated during the production of the optical modules. To overcome a possible bottleneck in the production process of testing and calibration of the massive amount of photomultipliers for KM3NeT, we developed the Dark Box instrument to accelerate the process. The Dark Box setup is designed to provide fast simultaneous automatic testing of 62 photomultipliers to verify their compliance to requirements for timing and ToT resolution and the occurrence of spurious pulses. In addition, the Dark Box can be easily converted into a general instrument for testing and calibrating large amounts of photomultipliers other than those for KM3NeT. We report on the design and performance of the Dark Box instrument for the high-statistics measurement of the characteristics of photomultipliers and of their calibration.
Speaker: Paolo Piattelli (INFN)
• 3:30 PM
The data acquisition system of the KM3NeT detector 1h
The KM3NeT neutrino telescope is part of a deep-sea research infrastructure being constructed in the Mediterranean Sea. The basic element of the detector is the Detection Unit, a 700 meter long vertical structure hosting 18 Digital Optical Modules (DOMs). The DOM comprises 31 3'' photomultiplier tubes (PMTs), various instruments to monitor environmental parameters, and the electronic boards for the digitization of the PMT signals and the management of data acquisition. Dedicated readout electronics have been developed and are installed inside each DOM, allowing to measure the time of arrival and the duration of photon hits, on each of the 31 photomultiplier tubes, with a time resolution of 1 ns. Moreover, the data transmission system of the DOMs supports a data transfer rate up to 250 Mbps, which corresponds to a photon-hit rate of 15 kHz on each PMT. Due to the extreme operation conditions of the abyssal site, the all-data-to-shore concept is used in order to minimize the complexity of the offshore detector. The processing of the data transmitted to onshore is performed by the Trigger and Data Acquisition System (TriDAS). The networking infrastructure and computing resources are conceived to be modular and scalable in order to manage the full data rate from the final cubic-kilometer scale telescope. The electronics and the DAQ system described in the poster are currently under test in the first Detection Unit deployed offshore Toulon and operated since spring 2015.
Speaker: Paolo Piattelli (INFN)
• 3:30 PM
The electron spectrum from annihilation of Kaluza-Klein dark matter in the Galactic halo 1h
The Kaluza-Klein (KK) particles, which are the feasible candidate for the dark matter, produce electrons and positrons when they annihilate in the Galactic halo. When the electrons and positrons propagate in the Universe, their direction is randomaized by the Galactic magnetic field, and energy is reduced by some energy loss mechanisms. We calculate the electron and positron spectrum expected from KK particle annihilation to be observed at Earth, taking account of propagation effects in the Galaxy. We assume the lightest KK particle (LKP) in the mass range from 500 GeV to 1000 GeV is the dark matter consisting of the Galactic halo, and we treat the particle spectra from LKP annihilation which include electron-positron component from two-body decays and continuum'' emission. We calculate the effects of diffusion and energy loss in the Galaxy, and analyze the resulting spectra. These spectra strongly depend on the LKP mass and will be compared with recent observational data taking account of energy resolution of detectors. We can set some constraints for the boost factor of dark matter concentration in the Galactic halo. In addition, we will discuss the recent result on positron fraction based on our calculation.
Speaker: Mr Satoshi Tsuchida (Ritsumeikan University)
• 3:30 PM
The KM3NeT Multi-PMT Digital Optical Module 1h
The KM3NeT collaboration is currently constructing the first phase of a cubic kilometer-scale neutrino detector in the Mediterranean Sea. The basic detection element, the Digital Optical Module (DOM), houses 31 three-inch PMT’s inside a 17 inch glass sphere. This multi-PMT concept yields a factor three increase in photocathode area, compared to a design with a single 10 inch PMT, leading to a significant cost reduction. Moreover, this concept allows for an accurate measurement of the light intensity (photon counting) and offers directional information with an almost isotropic field of view. We will discus these aspects and the enabling technologies, which include 3D-printed support structures, and custom low-powered PMT bases, which provide the HV and digitization of the analog signal. An FPGA based readout system transfers all sub-ns timestamped photon signals to shore via optical fibers. The DOM design has been validated and its physics potential have been proven in currently operational prototypes deployed in the French and Italian sites at 2500m and 3500m depth respectively.
Speakers: Dr Daan van Eijk (Nikhef), R Bruijn (Nikhef)
• 3:30 PM
The Mechanical structure and deployment procedure of the KM3NeT detection unit. 1h
In this paper we provide a detailed description of the mechanical structure of the 750 m high KM3NeT detection unit. The choices made for the different materials and their behaviour under the loads expected during deployment an during the lifetime of the experiment will be discussed, as will the motion of the unit under influence of the sea currents. The unique method of deployment, which entails unfurling of the unit from the seabed using a purpose built launcher, will be described.
Speaker: Prof. Paul Kooijman (University of Amsterdam)
• 3:30 PM
The observability of gamma-ray spectral features from Kaluza-Klein dark matter annihilation 1h
The lightest Kaluza-Klein particle (LKP), which appears in the theory of universal extra dimensions, is one of the good candidates for cold dark matter. We assume the LKP mass ranges from 500 GeV to 1000 GeV. We focus on the LKP annihilation modes which contain gamma-rays as final products. The gamma-ray spectrum from LKP annihilation has a characteristic peak structure near the LKP mass (`lines'') from two-body decays and continuum emission. Gamma rays do not lose energy during propagation after production near the galactic center where dark matter concentration is expected, so we can treat it easier than electron. We investigate the detectability of this peak structure by considering energy resolution of near-future detector, and calculate the expected count spectrum of the gamma-ray signal. The observed gamma-ray spectrum will show the peak clearly, if the LKP mass is heavier. In contrast, if the LKP mass is light, constraint for the boost factor becomes strictly. Detecting such peak structure would be conclusive evidence that dark matter is made of LKP.
Speaker: Mr Satoshi Tsuchida (Ritsumeikan University)
• 3:30 PM
The optical module of the Baikal-GVD neutrino telescope 1h
The BAIKAL-GVD neutrino telescope in Lake Baikal is intended for studying astrophysical neutrino fluxes by recording the Cherenkov radiation of the secondary muons and showers generated in neutrino interactions. The first stage of BAIKAL-GVD will be equipped with about 2400 optical modules. Each of these optical modules consists of a large area photomultiplier R7081-100 made by Hamamatsu Photonics and its associated electronics housed in a pressure resistant glass sphere. We describe the design of the optical module, the front-end electronics and the laboratory characterization and calibration before deployment.
Speaker: Bair Shaybonov (JINR)
• 3:30 PM
Time and amplitude calibration of the Baikal-GVD neutrino telescope 1h
The first stage of the Baikal-GVD neutrino telescope will be composed of more than two thousand light sensors, Optical Modules (OMs), installed deep underwater in Lake Baikal. We describe developed calibration methods which use OM LEDs, the calibration laser source, atmospheric muons etc. and discuss the performance of these methods.
Speaker: Bair Shaybonov (JINR)
• 3:30 PM
Time synchronization and time calibration in KM3NeT 1h
The KM3NeT neutrino telescope is a next generation Cherenkov array containing thousands of optical modules being installed in deep sea at a depth larger than 2500 m and more than 40 km distance from the shore. For the precise event reconstruction sub-nanosecond precision synchronization between modules is required. Its realization exploits the White Rabbit system to synchronize clocks between nodes through Ethernet over optical fiber. This system was modified for the KM3NeT architecture that is designed for clock distribution based on a common broadcast line. The calibration procedure for electronics latencies, fiber path asymmetries and wavelength dependent light velocity on fiber is described. LED beacons installed on optical modules, laser beacons at the sea bottom and K40 decays are also used to monitor the detector time synchronization in situ. Application of the time calibration procedure to the first detection unit string with 18 optical modules and it performance will be presented.
Speaker: Dr Mieke Bouwhuis (NIKHEF)
• 3:30 PM 4:30 PM
Poster 1 GA Mississippi Foyer

Mississippi Foyer

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 3:30 PM
A data mining approach to recognizing source classes for unassociated gamma-ray sources 1h
The Fermi-LAT 3rd source catalog (3FGL) provides spatial, spectral, and temporal properties for 3033 gamma-ray sources. While 2041 sources in the 3FGL are associated with AGNs (58% of the total), pulsars (5%) and the other classes (4%), 992 sources (33%) remain as unassociated sources. In recognizing source classes for unassociated gamma-ray sources of the Fermi-LAT source catalogs, various data mining techniques have been applied, e.g. artificial neural network and classification tree. As a robust alternative to these data mining techniques, we present the Mahalanobis Taguchi (MT) method to recognize source classes. The MT method creates a multidimensional Mahalanobis space from characteristic variables of a normal class (e.g. AGN) to identify sources of the normal class from those of the other classes with Mahalanobis distances. In this paper, we present the results of the source classification for the unassociated gamma-ray sources in 3FGL by applying the MT method.
Speaker: Prof. Kenji Yoshida (Shibaura Institute of Technology)
• 3:30 PM
A major electronics upgrade for the H.E.S.S. Cherenkov telescopes 1-4 1h
Speaker: Stefan Klepser (DESY)
• 3:30 PM
A new time-dependent likelihood technique for detection of gamma-ray bursts with IACT arrays 1h
In imaging atmospheric Cherenkov telescope arrays (IACTs), the standard method of statistically inferring the existence of a source is based on the maximum likelihood method of Li&Ma (1983). We will present a new statistical approach, also based on maximum likelihood theory, which takes into account a priori knowledge of the source light curve. This approach is especially useful for observations of rapidly decaying gamma-ray bursts (GRBs). Using Monte Carlo simulations, the new maximum likelihood test statistic is evaluated under realistic conditions for GRBs observed by current generation IACT arrays, and a moderate improvement in sensitivity is projected. To calculate the improvement, we conservatively assume that the Li&Ma integration time has been optimally chosen, which isn't possible in reality without prior knowledge of the burst fluence. The sensitivity improvement depends on the decay index of the burst and the observing delay, but is projected to be approximately 30% for a typical observation near the threshold of detection (typical is defined as a burst observed with a 2min delay and that decays as a power law of index -1). An even larger improvement is projected for quickly observed, rapidly decaying GRBs. The method is shown to be relatively resilient to uncertainties in the light curve, as long as it still captures the decaying nature of the GRB flux. We will also discuss results established by using this technique to analyze VERITAS GRB observations.
Speaker: Mr Ori Weiner (Columbia University)
• 3:30 PM
Advanced models for AGN emission 1h
Active Galactic Nuclei have been in the focus of gamma-ray telescopes for the past years. With the ever growing sample of AGN the need for physically motivated, self-consistent modeling is also growing. The major questions to be answered by models are: What are the main constituents of AGN jets? What are the acceleration mechanisms? Are AGN possible accelerators for UHECR and possible source of UHE neutrinos? We will present new modeling approaches for AGN, which have a focus on the self-consistent approach. Two types of models have emerged from our work: A homogeneous model containing acceleration via Fermi mechanisms, leptonic and photo-hadronic radiation mechanisms and time variability. And a spatially extended model containing the same radiation processes, but a pitch-angle resolved acceleration process. The results contain the radio signature of extended jets with predictions for the motion of radio cores correlated with TeV emissions and also possible discrimination criteria for hadronic and leptonic radiation models.
Speaker: Felix Spanier (North-West University)
• 3:30 PM
Analysis of GeV-band gamma-ray emission from SNR RX J1713.7-3946 1h
RX J1713-3946 is the brightest shell-type supernova remnant (SNR) of the TeV gamma-ray sky. Earlier Fermi-LAT results on low energy gamma-ray emission suggested that, despite large uncertainties in the background determination, the spectrum is inconsistent with a hadronic origin. We update the GeV-band spectra using improved estimates for the diffuse galactic gamma-ray emission and more than double the volume of data. We further investigate the viability of hadronic emission models for RX J1713-3946. We produced a high-resolution map of the diffuse Galactic gamma-ray background corrected for the HI self-absorption and used it in the analysis of more than five years worth of Fermi-LAT data. We used hydrodynamic scaling relations and a kinetic transport equation to calculate the acceleration and propagation of cosmic rays in SNR. We then determined spectra of hadronic gamma-ray emission from RX J1713-3946, separately for the SNR interior and the cosmic-ray precursor region of the forward shock, and computed flux variations that would allow us to test the model with observations. We find that RX J1713-3946 is now detected by Fermi-LAT with very high statistical significance, and the source morphology is best described by that seen in the TeV band. The measured spectrum of RX J1713-3946 is hard with index $\gamma=1.53\pm0.07$, and the integral flux above 500 MeV is $F = (5.5\pm1.1)\times10^{-9}$ photons cm$^{-2}$ s$^{-1}$. We demonstrate that scenarios based on hadronic emission from the cosmic-ray precursor region are acceptable for RX J1713-3946, and we predict a secular flux increase at a few hundred GeV at the level of around 15% over ten years, which may be detectable with the upcoming Cherenkov Telescope Array (CTA) observatory.
Speaker: Robert Brose (DESY)
• 3:30 PM
Analysis of the first observations with the new MAGIC Sum-Trigger-II 1h
The MAGIC telescopes were built with the aim of achieving the lowest possible energy threshold among the current generation of Cherenkov telescopes. This was mandatory to detect sources with emission mainly below 100 GeV, as distant AGNs and pulsars. In 2009, the second MAGIC telescope started operation, and in the last years, a major upgrade of the system took place. One of the main improvements has been the development of a new version of the Sum-Trigger concept, valid for stereoscopic observations. This Sum-Trigger-II system was installed during Winter 2013/14, and since then, we have collected the first test data to characterize its scientific capabilities. In this contribution the results of the analysis of the first Crab pulsar data taken with the Sum-Trigger-II are shown, demonstrating the potential of this new system to study gamma-ray sources with high sensitivity above 40 GeV.
Speaker: Marcos López Moya (University Complutense of Madrid)
• 3:30 PM
Blazar Alerts with the HAWC Online Flare Monitor 1h
The High Altitude Water Cherenkov (HAWC) Gamma Ray Observatory monitors the gamma-ray sky in the 100 GeV to 100 TeV energy range with >95% uptime and unprecedented sensitivity for a survey instrument. The HAWC Collaboration has implemented an online flare monitor that detects episodes of rapid flaring activity from extragalactic TeV sources in the declination band from -26 to 64 degrees. This allows timely alerts to be sent to multiwavelength instruments without human intervention. The preliminary configuration of the online flare monitor achieves sensitivity to flares of at least 1 hour duration that attain an average flux of 10 times that of the Crab Nebula. While flares of this magnitude are not common, several flares reaching the level of 10 Crab have been observed in the TeV band in the past decade. With its survey capabilities and high duty cycle, HAWC will expand the observational data set on these particularly extreme flares. We will discuss results from the first alerts issued by the online flare monitor and the prospects for multiwavelength studies of blazar dynamics, the extragalactic background light, and the intergalactic magnetic field using extreme blazar flares detected by HAWC. We will also highlight upcoming improvements to the flare monitor that will extend its sensitivity to weaker flares.
Speaker: Dr Thomas Weisgarber (for the HAWC Collaboration)
• 3:30 PM
Constraining the properties of new gamma-ray MSPs with distance and velocity measurements 1h
The millisecond pulsar (MSP) luminosity distribution is useful to address e.g. contributions to the distribution of the diffuse positrons and gamma rays within our Galaxy. Gamma-ray luminosity versus spin-down power (Edot) is also a key observable to constrain emission models. The Shklovskii effect consists of an artificial increase of the apparent period derivative value (Pdot) over the intrinsic one due to the pulsar's transverse motion. Accounting for this effect can significantly change the Edot value in many cases: it depends on the MSP's distance and proper motion. In this contribution we will focus on the gamma-ray detection of four MSPs with the Fermi Large Area Telescope (LAT) and on parallax and proper motion measurements for an ensemble of gamma-ray MSPs using Nançay radio telescope data, that we use to compute the Shklovskii corrections and update the luminosity vs Edot relation, bringing new constraints on these pulsars' properties.
Speaker: Helene Laffon (CENBG)
• 3:30 PM
Construction of a medium size prototype Schwarzschild-Couder telescope as candidate instrument for the Cherenkov Telescope Array: Overview of mechanical and optical sub-systems. 1h
The design of a 9.5-m prototype Schwarzschild-Couder telescope (pSCT) with an aplanatic two-mirror optical system has been developed to evaluate its capabilities for the future Cherenkov Telescope Array Observatory (CTAO). The construction of this novel imaging atmospheric Cherenkov telescope (IACT) is scheduled for early autumn of 2015 at the Fred Lawrence Whipple Observatory in Southern Arizona, USA. The pSCT is expected to verify superior performance of this instrument (high angular resolution, wide field of view, reduced focal plane plate scale, high channel density low cost camera electronics, single photon counting operation regime, etc.) as compared to the traditional Davies-Cotton IACTs constructed for the VERITAS and HESS ground based gamma-ray observatories. An array of SC telescopes operating as a possible extension of the CTA installation is expected to significantly enhance the research capabilities of the observatory for very high-energy (E>100 GeV) gamma-ray astronomy. In this contribution we present the design overview of the pSCT mechanical and optical sub-systems and the status of the telescope construction.
Speaker: Prof. Vladimir Vassiliev (University of California Los Angeles)
• 3:30 PM
Cosmic ray acceleration and nonthermal emission from ultra-fast outflows in active galactic nuclei 1h
There is mounting evidence for the widespread existence of ultra-fast outflows in active galactic nuclei, which are powerful outflows of baryonic material approaching mildly relativistic velocities, observed as variable, blue-shifted X-ray absorption lines of ionized heavy elements. Occurring in both radio-loud and radio-quiet objects, they are plausibly interpreted as winds driven by the accretion disk, and their interaction with their environment may be the key cause of known correlations between the properties of supermassive black holes and their host galaxies. In such outflows, collisionless shocks are likely to form at different locations, either external shocks due to interaction with the ambient medium, or internal shocks due to inhomogeneities within the flow. We discuss the possibility of acceleration of electrons and hadrons at such shocks, including that of ultra-high-energy cosmic rays. Expectations for the consequent nonthermal emission from the radio band up to high-energy gamma-rays are also presented, and compared with existing data on selected objects of interest, such as ESO 323-G77 and 3C 120. Prospects for further observations with current and future instruments are addressed.
Speaker: Susumu Inoue (Institute for Cosmic Ray Research, University of Tokyo)
• 3:30 PM
Cosmic-Ray Induced Gamma-Ray Emission From Starburst Galaxies 1h
In star-forming galaxies, gamma rays are mainly produced through the collision of high-energy protons in cosmic rays and protons in the interstellar medium (ISM) (i.e. cosmic ray-induced π0 γ-radiation). For a “normal” star-forming galaxy like the Milky Way, most cosmic rays escape the Galaxy before such collisions, but in starburst galaxies with dense gas and huge star formation rate, most cosmic rays do suffer these interactions. We construct a “thick-target” model for starburst galaxies, in which cosmic rays are accelerated by supernovae, and escape is neglected. This model gives an upper limit to the gamma-ray emission and tests the calorimetry relation between gamma rays and cosmic rays for starbursts. Only two free parameters are involved in the model: cosmic-ray proton acceleration energy rate from supernova and the proton injection spectral index. We apply the model to five observed starburst galaxies: M82, NGC 253, NGC 1068, NGC 4945 and Circinus, and find the calorimetric relation holds for most of the starbursts, but for Circinus, other gamma-ray sources must be presented to explain for its GeV excess. The pionic gamma-ray emission is calculated from 10 MeV to 10 TeV, which covers the Fermi Gamma-ray Space Telescope (Fermi) energy range. We also apply the model to the extragalactic gamma-ray background emission(EGB) by assuming all star-forming galaxies are calorimetric, finding that star-forming galaxies cannot make the entire signal, other gamma-ray sources must also exist.
Speaker: Ms Xilu Wang (University of Illinois at Urbana and Champaign)
• 3:30 PM
Creating a high-resolution picture of Cygnus with the Cherenkov Telescope Array 1h
The Cygnus region hosts one of the most remarkable star-forming regions in the Milky Way. Indeed, the total mass in molecular gas of the Cygnus X complex exceeds 10 times the total mass of all other nearby star-forming regions. Surveys at all wavelengths, from radio to gamma-rays, reveal that Cygnus contains such a wealth and variety of sources---supernova remnants (SNRs), pulsars, pulsar wind nebulae (PWNe), Hii regions, Wolf-Rayet binaries, OB associations, microquasars, dense molecular clouds and superbubbles---as to practically be a galaxy in microcosm. The gamma-ray observations along reveal a wealth of intriguing sources at energies between 1 GeV and tens of TeV. However, a complete understanding of the physical phenomena producing this gamma-ray emission first requires us to disentangle overlapping sources and reconcile discordant pictures at different energies. This task is made more challenging by the limited angular resolution of instruments such as the Fermi Large Area Telescope, ARGO-YBJ, and HAWC and the limited sensitivity and field of view of current imaging atmospheric Cherenkov telescopes (IACTs). The Cherenkov Telescope Array (CTA), with its improved angular resolution, large field of view, and order of magnitude gain in sensitivity over current IACTs, has the potential to finally create a coherent and well-resolved picture of the Cygnus region between a few tens of GeV and a hundred TeV. We describe a proposed strategy to study the Cygnus region using CTA data, which combines a survey of the whole region at 65°< l < 85° and -3.5° < b < 3.5° with deeper observations of two sub-regions that host rich groups of known gamma-ray sources.
Speaker: Amanda Weinstein (Iowa State University)
• 3:30 PM
Development of a SiPM Camera for a Schwarzschild-Couder Cherenkov Telescope for the Cherenkov Telescope Array 1h
We present a development of a novel 11328 pixel silicon photomultiplier (SiPM) camera for use with a ground-based Cherenkov telescope with Schwarzschild-Couder optics as a possible mid-size telescope for the Cherenkov Telescope Array (CTA), which is the next generation very-high-energy gamma-ray observatory. . The finely pixelated camera samples air-shower images with more than twice the optical resolution of cameras that are used in current Cherenkov telescopes. Advantages of the higher resolution will be a better event reconstruction yielding improved background suppression and angular resolution of the reconstructed gamma-ray events, which is crucial in morphology studies of, for example, Galactic particle accelerators and the search for gamma-ray halos around extragalactic sources. Packing such a large number of pixels into an area of only half a square meter and having a fast readout directly attached to the back of the sensors is a challenging task. For the prototype camera development SiPMs from Hamamatsu with through silicon via (TSV) technology are used. We give a status report of the camera design and highlight a number of technological advancements that made this development possible.
Speaker: Nepomuk Otte (Georgia Institute of Technology)
• 3:30 PM
Divergent pointing with the Cherenkov Telescope Array for surveys and beyond 1h
The galactic and extragalactic surveys are two of the main proposed legacy projects of the Cherenkov Telescope Array (CTA). Considering Cherenkov telescopes field of view (<10°), the time needed for those projects is large. The many telescopes of CTA will allow taking full advantage of new pointing modes in which telescopes point slightly offset from one another. This divergent pointing mode leads to an increase of the array field of view (~ 14° or larger) with competitive performance compared to normal pointing. We present here a study of the performance of the divergent pointing for different array configurations and number of telescopes. We show that for a fixed survey sensitivity, using divergent pointing instead of normal pointing results in a non-negligible gain in observing time and reduced fluctuations in survey depth. We review multiple science cases benefiting from the large field-of-view offered by the divergent pointing.
Speaker: Lucie Gerard
• 3:30 PM
Exploiting the time of arrival of Cherenkov photons at the 28 m H.E.S.S. telescope for background rejection: Methods and performance 1h
In 2012, the High Energy Stereoscopic System (H.E.S.S.) was expanded by a fifth telescope (CT5). With an enormous effective mirror diameter of 28 m, CT5 is able to detect the Cherenkov light of very faint gamma-ray air showers, thereby significantly lowering the energy threshold of this telescope compared to the other four telescopes. Extracting as much information as possible from the recorded shower image is crucial for background rejection and to reach an energy threshold of a few tens of GeV. The camera of CT5 is conceived to register the time of the charge pulse maximum with respect to the beginning of the 16 ns integration window of each pixel. This information can be utilised to improve the event reconstruction. It also helps to reduce the background contamination at low energies. We present new techniques for background rejection based on CT5 timing information and evaluate their performance.
Speaker: Raphaël Chalmé-Calvet (LPNHE)
• 3:30 PM
Exploring the gamma ray sky above 30 TeV with LHAASO 1h
The gamma ray sky at energies above a few tens of TeV is almost completely unexplored. Sources of photons above ~30 TeV must however exist because cosmic rays are accelerated in the Milky Way at least up to the knee energy. Photon emission in this energy range, with a high degree of confidence, has an hadronic origin and traces the proton and nuclei acceleration sites. Gamma ray astronomy above 30 TeV is therefore of fundamental importance for the identification of cosmic ray sources. LHAASO is a project of a multi-component air shower detector, to be built in Sichuan, China, at 4410 m of altitude. One element of the detector, the KM2 array, a grid of scintillators and muon detectors distributed over an area of ~1 Km$^2$ will be able to monitor in one year the northern sky at 100 TeV with a sensitivity of 1% of the Crab Nebula flux. In this paper the capabilities of LHAASO in gamma ray astronomy above 30 TeV are reviewed, and the scientific potential in identifying or constraining galactic and extragalactic cosmic ray sources is discussed.
Speaker: Silvia Vernetto (Istituto Nazionale di Astrofisica)
• 3:30 PM
FACT - Charged Cosmic Ray Particles as a Tool for Atmospheric Monitoring 1h
FACT is the first Imaging Air Cherenkov Telescope to use solid-state photosensors (G-APD/SiPM) in order to measure the light flashes induced by air-showers. A vital part of the telescope system is the atmosphere. Typically, external devices such as LIDARs are used to quantify the quality of the atmospheric condition. Due to the exceptional stability of G-APD sensors, a different approach to monitor the quality of the atmosphere can be implemented. Due to this stability variations of the measured charged cosmic ray flux are an effect of changes of the atmosphere. Trigger rates of FACT are already used to identify strong disturbances for example clouds or Calima. In a new study, we use the data taken during the past years to investigate more subtle effects like the difference between summer and winter atmosphere predicted by Monte Carlo simulations.
Speaker: Dr Dorothee Hildebrand (ETH Zurich)
• 3:30 PM
FACT - Performance of the First SiPM camera 1h
The First G-APD Cherenkov Telescope (FACT) is the first operational test of the performance of silicon photomultipliers (SiPM) in Cherenkov Astronomy. These novel photon detectors promised to be an inexpensive and robust alternative for vacuum photomultiplier tubes, but had never been applied in an imaging airshower cherenkov telescope (IACT) up to now. For more than three years FACT has operated on La Palma, Canary Islands (Spain), for the purpose of long-term monitoring of astrophysical sources. Stable performance of the photo detectors is crucial and therefore has been studied in great detail. Special care has been taken in regards to their temperature and overvoltage dependence through implementation of a feedback method in order to keep their properties stable. Several indipendent long term measurements were conducted to analyse and verify SiPM gain stability. Dark count spectra, which also make for an excellent self calibration mechanism, were used to study and correct for temperature dependencies. Ratescans make it possible to derive a method, for quickly finding apropriate trigger thresholds by measuring pixel currents, and thus allow for a consistent data aquisition rate. Dedicated measurements with an LED flasher are used to study the correct application of SiPM bias voltages. In this talk, the results of the long term studies will be presented and the applicability of SiPMs in IACTs for long term monitoring will be shown.
Speaker: Dominik Neise (ETH Zurich)
• 3:30 PM
FACT – Influence of SiPM Crosstalk on the Performance of an Operating Cherenkov Telescope 1h
The First G-APD Cherenkov telescope (FACT) is the first operational telescope of its kind with a camera equipped with silicon photon detectors (G-APD aka. SiPM). SiPMs have a high photon detection efficiency (PDE), while being more robust to bright light conditions than the commonly used photo-multiplier tubes. This technology has allowed us to increase the duty cycle beyond that of the current generation of imaging air Cherenkov telescopes. During the last four years, the operation of FACT has proven that SiPMs are a suitable photon detectors for an application in the field of earth-bound gamma-ray astronomy. Nevertheless, it has been argued that crosstalk, after-pulses and dark counts are the main drawback of SiPMs, as these effects produce photon-like signals that would add up the signal background. Consequently, it is necessary to understand their impact on the analysis of data from FACT. In this presentation, we will show results of a study about the influence of different settings of crosstalk and dark counts on the performance of FACT i.e. its energy resolution and energy threshold. For that purpose, we used Monte Carlo simulations and compared them to actual data from the SiPM camera of FACT.
Speaker: Mr Jens Buß (TU Dortmund)
• 3:30 PM
FACT – Novel mirror alignment using Bokeh and enhancement of the VERITAS SCCAN alignment method 1h
Imaging Air Cherenkov Telescopes, including the First G-APD Cherenkov Telescope (FACT), use segmented reflectors. These offer large and fast apertures for little resources. However, one challenge of segmented reflectors is the alignment of the single mirrors to gain a sharp image. For Cherenkov telescopes, high spatial and temporal resolution is crucial to reconstruct air shower events induced by cosmic rays. Therefore one has to align the individual mirror positions and orientations precisely. Alignment is difficult due to the large number of degrees of freedom and because most techniques involve a star. Most current methods are limited, because they have to be done during good weather nights which overlaps with observation time. In this contribution, we will present the mirror alignment of FACT, done using two methods. Firstly, we show a new method which we call Bokeh alignment. This method is simple, cheap and can even be done during daytime. Secondly, we demonstrate an enhancement of the SCCAN method by F. Arqueros et al., and first implemented by the McGill VERITAS group. Using a second camera, our enhanced SCCAN is optimized for changing weather, changing zenith distance, and changing reference stars. Developed off site in the lab on a 1/10th scale model of FACT, both our alignment methods resulted in a highly telescope independent procedure, e.g. both our methods run without communication to the telescope's drive. We compare alignment results by using the point spread function of star images, ray tracing simulations, and overall muon rates before and after the alignment.
Speaker: Sebastian Mueller (ETH Zuerich)
• 3:30 PM
Fermi Gamma-ray Burst Monitor Capabilities for multi-messenger time-domain astronomy 1h
Owing to its wide sky coverage and broad energy range, the Fermi Gamma-ray Burst Monitor (GBM) is an excellent observer of the transient hard X-ray sky. GBM detects about 240 triggered Gamma-Ray Bursts (GRBs) per year, including over 30 which also trigger the Swift Burst Alert Telescope (BAT). The number of GRBs seen in common with Swift is smaller than expected from the overlap in sky coverage because GBM is not as sensitive as the BAT and the GBM GRB population is thus skewed to the brighter, closer bursts. This population includes about 45 short GRBs per year, giving GBM an excellent opportunity to observe the electromagnetic counterpart to any gravitational wave candidate resulting from the merger of compact binary members. The same characteristics make GBM an ideal partner for neutrino searches from nearby GRBs, and for the elusive Very-High Energy (VHE) counterparts to GRBs. With the deployment of the next-generation gravitational-wave detectors (Advanced LIGO/VIRGO) and VHE experiments (CTA and HAWC) within the lifetime of the Fermi Gamma-ray Space Telescope, the prospects for breakthrough observations are good.
Speaker: Valerie Connaughton
• 3:30 PM
Fermi LAT observations of high energy gamma rays from the Moon 1h
We have measured the gamma-ray emission spectrum of the Moon using a the data collected by the Large Area Telescope onboard the Fermi satellite during its first 77 months of operation, in an energy range from 30 MeV up to a few GeV. We have developed a full Monte Carlo simulation describing the interactions of cosmic rays with the Moon surface and the subsequent production of gamma rays using the FLUKA code. The observations can be explained in the framework of this model, where the production of gamma rays is due to the interactions of charged cosmic rays with the surface of the Moon. From the simulation results we have also inferred the cosmic-ray proton spectrum at low energies starting from the gamma-ray measurements. A time evolution study of the gamma-ray emission will be also presented.
Speaker: Francesco Loparco (Universita e INFN, Bari (IT))
• 3:30 PM
FIPSER a novel low cost and high performance readout for astrophysics 1h
Low-cost and low-power digitization systems become increasingly important in particle-physics and particle-astrophysics experiments as the number of channels is continuously rising. Specialized readout concepts have been developed in the past that aimed at lower costs and made detector systems with many ten thousand channels feasible. As the number of channels in experiments is still on the rise new readout concepts are needed that meet upcoming demands. We propose a novel readout system FIPSER (FI xed Pulse Shape Efficient Readout) that is primarily aimed for the digitization of detector signals that are a few nanoseconds long and vary in amplitude, but do not change their shape. FIPSER has the potential to lower the costs of the readout, including the front-end electronics, by an order of magnitude to less than $10 and power consumption to less than 50mW per channel. FIPSER will make new groundbreaking experiments possible that have previously not been feasible due to conflicting power, thermal, and performance requirements. Speaker: Nepomuk Otte (Georgia Institute of Technology) • 3:30 PM GAMERA -⁠ a new modeling package for non-⁠thermal spectral modeling 1h GAMERA is a new open-source C++ package which handles the spectral modelling of non-thermally emitting astrophysical sources in a simple and modular way. It allows the user to devise time-dependent models of leptonic and hadronic particle populations in a general astrophysical context (including SNRs, PWNs and AGNs) and to compute their subsequent photon emission. Moreover, this package also contains the necessary tools to create Monte-Carlo population synthesis models. In this poster, I will explain the basic design concept of GAMERA and present several examples of its implementation. Speaker: Dr Joachim Hahn (MPIK) • 3:30 PM Gamma-Ray and Cosmic Ray Escape in Intensely Star-Forming Systems 1h Regions of intense star-formation naturally generate high number densities of cosmic rays and as such, they are of particular interest as potential contributors to the extragalactic gamma-ray background (EGRB) and as potential sources of very high-energy cosmic rays (VHECRs). While models of the starburst contribution to the EGRB often assume cosmic rays are confined in starbursts, cosmic rays must escape from these galaxies if they contribute to the spectrum of VHECRs as observed at Earth. The conditions in star-forming galaxies which are responsible for such high cosmic-ray injection rates also lead to large gamma-ray fluxes, except in the case of Compton thick systems where the highest energy photons are prevented from escaping. To address these contrasting ideas, we model the gamma-ray fluxes from galaxies where cosmic rays are confined and from galaxies with strong galactic winds and explore the relationship between cosmic-ray confinement and gamma-ray absorption. We present results for the nearby starburst galaxy M82 and the ultraluminous infrared galaxy Arp 220 as examples. Speaker: Tova Yoast-Hull (University of Wisconsin-Madison) • 3:30 PM Gamma-ray properties of low luminosity AGNs 1h We present results of the analysis of the Fermi-LAT data from low-luminosity Seyfert galaxies, whose X-ray spectra are consistent with predictions of the hot flow (ADAF) model. We use our precise hot flow model (fully GR and with a Monte Carlo computation of radiative processes) to fit the X-ray data and then we estimate the gamma-ray flux from hadronic processes in the two-temperature plasma forming the flow. We find that the strongest gamma-ray signal may be expected from NGC 4258 and NGC 4151 and at the positions of both objects we find marginally significant signals, with sigma ~ 3. For all studied objects we derive upper limits (UL) for the gamma-ray flux. By comparing them with predictions of the ADAF model we find that the Fermi-LAT ULs strongly constrain non-thermal acceleration processes in hot flows (with the energy content in the non-thermal component of proton distribution amounting to at most ~10%) as well as the values of some crucial parameters, most significantly the magnetic field strength. We also find that the component above 4 GeV in the gamma-ray spectrum of Cen A may be due to hadronic emission from a hot accretion flow with parameters consistent with the above constraints. Under the assumption that this emission is produced by protons accelerated up to ~10^16 eV, as predicted by some acceleration models, we calculate the expected neutrino flux. Speaker: Mr Rafal Wojaczynski (Department of Astrophysics, University of Lodz) • 3:30 PM Gamma-rays from accretion process onto millisecond pulsars 1h We consider a simple scenario for the accretion of matter onto rotating, magnetised neutron star in order to understand the processes in the inner pulsar magnetosphere during the transition stage between different accretion modes. We analyse a quasi-spherical accretion process onto rotating, magnetized compact object in order to search for radiative signatures which could accompany the accretion process onto a millisecond pulsar close to the transition stage. It is argued that different accretion modes can be present in a single object for specific range of parameters characterising the millisecond pulsar and the surrounding medium. We show that the radiation processes characteristic for the ejecting pulsar, i.e. curvature and synchrotron radiation produced by primary electrons in the pulsar outer gap, can be accompanied by the inverse Compton radiation produced by secondary leptons which up-scatter thermal radiation from the hot polar cap region caused by the matter accreting onto the neutron star surface. We conclude that during the transition from the pure ejector to the pure accretor mode (intermediate accretion state) additional components can appear in the$\gamma$-ray spectra of millisecond pulsars. This additional spectral component could allow to constrain the particle content of the pulsar inner magnetosphere such as the multiplicity and energies of secondary leptons. Speaker: Wlodek Bednarek (University of Lodz) • 3:30 PM GRAINE project: An overview and status of the 2015 balloon-borne experiment with emulsion gamma-ray telescope 1h The observation of high-energy cosmic gamma-rays provides us with direct information of high-energy phenomena in the universe. Currently, AGILE and Fermi-LAT are observing gamma-ray sky and many understandings are being brought to us. However, past and current observations have significant limitations. The improvement of angular resolution and polarization sensitivity is one of keys for a breakthrough of the limitations. We are pushing forward GRAINE project, 10MeV-100GeV cosmic gamma-ray observation with a precise (0.08deg@1-2GeV) and polarization sensitive large aperture area ($\sim$10m$^2$) emulsion telescope by repeated long duration balloon flights. We demonstrated the feasibility and performance of the emulsion gamma-ray telescope using accelerator beams with gamma-rays/electrons/muons and atmospheric gamma-rays at mountain height. In 2011, the first balloon-borne, emulsion gamma-ray telescope experiment was successfully performed with a 125cm$^2$aperture area and 4.3 hour flight duration. We demonstrated the working and performance of the emulsion gamma-ray telescope at a balloon flight for the first time. And the first understanding of the background was obtained with the emulsion gamma-ray telescope at a balloon flight. Based on the experience and achievements of the 2011 balloon experiment, we are planning a next balloon experiment on Japan-Australia scientific ballooning at Alice Springs with a 3600 cm$^2$aperture area and$\sim$1day flight duration in May 2015. In the next balloon experiment, we aim to detect the Vela pulsar, a well-known bright gamma-ray source, with more than 5$\sigma$significance and to demonstrate the overall performance of the emulsion gamma-ray telescope. Then, we will start the observation with the highest imaging resolution and polarization sensitivity. And phase resolving of the pulse emission from the Vela pulsar will be also challenged. An overview and status of the 2015 balloon experiment are presented. Speaker: Dr Satoru Takahashi (Kobe University) • 3:30 PM GRAINE project: Flight data analysis of balloon-borne experiment in 2015 with emulsion gamma-ray telescope 1h GRAINE is a balloon-borne experiment to observe cosmic gamma-ray with precise angular resolution and polarization sensitivity. Main gamma-ray detector is nuclear emulsion which can record three dimensional charged particle track with sub-micron position accuracy. We use multi-stage shifter technique in order to give time information to penetrating tracks of nuclear emulsion. Arrival direction of gamma-ray can be reconstructed to the celestial sphere by combining attitude data from star camera. By measuring the beginning of electron-positron pair with nuclear emulsion, our telescope can be achieved gamma-ray angular resolution one order of magnitude better than Fermi-LAT, and polarization sensitivity. First balloon-borne experiment of GRAINE was performed in 2011 in TARF, Japan. Equipment of our telescope operated completely well and we measured atmosphere gamma-ray which are background when we observe cosmic gamma-ray. Second balloon-borne experiment will be done in May 2015 in Alice Springs, Australia by JAXA international program. We aim to detect the Vela pulsar and also demonstrate the angular resolution best ever gamma-ray telescope. In this experiment, we overall use new type nuclear emulsion which are researching and developing at Nagoya University to improve sensitivity for charged particle. Emulsion films were transported to the University of Sydney by plane, and emulsion's handling such as resetting, drying, and packing will be performed there. For the second balloon experiment, the following equipment will be installed on a gondola with fabric pressure vessel: emulsion telescope, 3 star cameras, temperature meters, pressure meters, GPS systems, and batteries. After development of all emulsion films at University of Sydney, emulsion films will be scanned with fully automated readout system at Nagoya University. We will analyze using these scanned data to search gamma-ray events. Attitude data using star cameras will also be analyzed. Flight data analysis of GRAINE second balloon-borne experiment in 2015 is presented. Speaker: Mr Keita OZAKI (Kobe University) • 3:30 PM H.E.S.S. discovery of very-high-energy gamma-ray emission of PKS 1440-389 1h Blazars are the most abundant class of known extragalactic very-high-energy (VHE, E>100 GeV) gamma-ray sources. However, one of the biggest difficulties in investigating their VHE emission resides in their limited number, since less then 60 of them are known by now. In this contribution we report on the H.E.S.S. observations of the BL Lac object PKS 1440-389. This source has been selected as target for H.E.S.S. based on its high-energy gamma-ray properties measured by Fermi-LAT. The extrapolation of this bright, hard-spectrum gamma-ray blazar into the VHE regime made a detection on a relatively short time scale very likely, despite its uncertain redshift. H.E.S.S. observations were carried out with the 4-telescope array from March to May 2012 and resulted in a clear detection of the source. Contemporaneous multi-wavelength data will be used to construct its spectral energy distribution and we will discuss possible emission mechanisms explaining the observed broad-band emission of PKS 1440-389. Speaker: Heike Prokoph (Linnaeus University) • 3:30 PM HAWC: Design, Operation, Reconstruction and Analysis 1h The High-Altitude Water Cherenkov (HAWC) Observatory was completed and began full operation in early 2015. The detector consists of an array of 300 water tanks, each containing ~200 tons of purified water and instrumented with 4 PMTs. Located at an elevation of 4100m a.s.l. near the Sierra Negra volcano in central Mexico, HAWC has a threshold for gamma-ray detection well below 1 TeV and a sensitivity to TeV-scale gamma-ray sources an order of magnitude better than previous air-shower arrays. The detector operates 24 hours/day and observes the overhead sky (~2 sr), making it an ideal survey instrument. We describe the configuration of HAWC with an emphasis on how the design was optimized, including the size depth and spacing of the water tanks, the positioning of the PMTs and the requirements of the readout system. We also describe how the data are acquired, reconstructed, and analyzed. Finally, we will demonstrate the sensitivity of the detector using the observation of the Crab plerion. This paper serves as a detailed technical description of the foundations of the numerous analyses presented at this meeting by members of the HAWC collaboration. Speaker: Andrew Smith (University of Maryland, College Park) • 3:30 PM HESS observations of PKS 1830-211 1h PKS 1830-211 is a lensed blazar located at z=2.5. The recent addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity towards low energies, providing access to gamma-ray energies down to 30 GeV. Data towards PKS1830-211 were taken with CT5 in August 2014, following a flare alert by the Fermi collaboration at the beginning of the month. The H.E.S.S observations were aimed at detecting a gamma ray flare delayed by ~25 days from the Fermi flare. These HESS data are presented and discussed. Speaker: Jean-Francois Glicenstein (CEA) • 3:30 PM High energy emission from extended region within the blazar jet during quiet gamma-ray state 1h During the quiet$\gamma$-ray state of blazars the high energy emission is likely to be produced in the extended part of the inner jet in which the conditions can change significantly. Therefore, homogeneous SSC model is not expected to describe correctly the quiet state emission features. We consider inhomogeneous SSC model for the large part of the inner jet in which synchrotron and IC emission of relativistic electrons is taken into account self-consistently by applying the Monte Carlo method. The results of calculations are compared with the observations of some BL Lacs in the low state. Speaker: Piotr Banasiński (University of Lodz) • 3:30 PM High energy gamma-ray study of the microquasar 1E 1740.7-2942 with Fermi-LAT 1h The microquasar 1E 1740.7-2942, discovered by the Einstein satellite, is located near the Galactic Center at an angular distance of 50' from Sgr A*, and the brightest X-ray source above 20 keV in the Galactic Center region. It has extended radio lobes reaching distances of up to a few parsecs and its core radio emission is variable. In X-ray energies it shows the spectral and timing properties similar to those of black hole candidates like Cyg X-1. GRANAT/SIGMA reported a burst of soft gamma-ray emission (300-600 keV) in 1990s which was interpreted as an electron-positron annihilation signal, but other satellite observations could not confirm the high energy feature reported by SIGMA, although a high energy tail extending up to 600 keV with a power-law photon index of$1.9\pm0.1has been reported by INTEGRAL, indicating a non-thermal process which might accelerate particles to even higher energies. In this paper we report the result of gamma-ray study of 1E 1740.7-2942 above 100 MeV using the six-year Fermi-LAT archival data, and its implication on particle acceleration process in microquasars is discussed. Speaker: Masaki Mori (Ritsumeikan University) • 3:30 PM Long term stability analysis on the MD-A under TIBET III array 1h The underground muon detector with water Cherenkov technique is constructed as the upgrad of the Tibet air shower array, aiming at a higher sensitivity for gamma-ray observation. In one of the modules (MD-A), the full-sealing large Tyvek bag is used as a closed? container. As the MD-A has been operated for more than one year, the long term stability of the performance of such detector is reported. Speakers: Mr LIU Cheng (IHEP, CAS), Mr QIAN Xiangli (IHEP, CAS) • 3:30 PM Long term variability study for the radio galaxy M87 with MAGIC 1h M 87 is the closest extragalactic VHE object located in the Virgo cluster of galaxies at a distance of ~16 Mpc (redshift z=0.00436). It is the first and brightest radio galaxy detected in the TeV regime, well studied from radio to X-ray energies. The structure of its relativistic plasma jet, which is misaligned with respect to our line of sight, is spatially resolved in X-ray (Chandra), optical and radio (VLA/VLBA) observations. Thus the time correlation between the TeV flux and emission at different wavelengths provides a unique opportunity to localize the VHE emission process occurring in active galaxy nuclei. In 2005, gamma-ray emission at TeV energies was detected for the first time in M87. The very high energy (VHE, E>100 GeV) gamma-ray emission displays strong flux variability on timescales as short as a day. For more than 10 years, along with X-ray, optical and radio bands, it has been monitored in the TeV band by imaging atmosphere Cherenkov telescopes such as MAGIC, HESS and VERITAS. In 2008 and 2010, M87 underwent several periods of TeV activities, and rapid flares with short timescale variability were detected. MAGIC continued to monitor M87 but no major flares were detected since 2010. However, the monitoring data set allows us to study the source in quiescent flux state. Here we present the status of these studies using the data from the last 4 years of MAGIC observations. Speaker: Ms Priyadarshini Bangale (MPI for Physics, Munich) • 3:30 PM Low multiplicity technique for GRB observation by LHAASO-WCDA 1h Detection of GeV photons from GRBs is crucial in understanding the most violent phenomenon in our universe. Due to the limited effective area of space-born experiment, very few GRBs are detected with GeV photons. Large area EAS experiments at high altitude can reach a much larger effective area around 10 GeV, for which single particle technique is usually used to lower the threshold energy but its sensitivity is poor due to losing of primary direction information. To reach an energy threshold as low as 10 GeV and keep the primary direction information at the same time, low multiplicity trigger is required, but random coincidences rather than cosmic ray showers overwhelms the signals, and it is a great challenge for traditional trigger logic and reconstruction algorithm to discriminate the signals from the noises. A new method is developed for LHAASO-WCDA to work under low multiplicity mode. With this technique, the LHAASO detector can even work under multiplicity as low as 2 while keeping the direction information at the same time. The sensitivity and expectation of LHAASO-WCDA with low multiplicity technique to GRBs are presented. Speakers: Prof. Hanrong Wu (Institute of High Energy Physics, CAS), Prof. Huihai He (Institute of High Energy Physics, CAS) • 3:30 PM Multiwavelength Analyses of Long-Term Lower Flux State Observations of Intermediate-Frequency-Peaked BL Lacertae Sources: W Comae and 3C 66A 1h Intermediate-frequency-peaked BL Lacertae objects (IBLs) are a class of blazars characterized by a spectral energy distribution (SED) with a lower-energy synchrotron peak than a majority of extragalactic sources detected by ground-based imaging atmospheric Cherenkov telescopes (IACTs). Because of this shift in the SED, the peak gamma-ray flux falls outside the very-high-energy regime (VHE, >100 GeV) covered by IACTs such as VERITAS, making IBLs difficult to detect except during infrequent times of elevated flux. However, the study of these sources in a lower flux state is essential for developing a complete understanding of the blazar paradigm. We present the results of multiwavelength analyses of long-term lower flux state observations completed for two IBL sources: W Comae and 3C 66A. For both sources, data from VERITAS were analyzed for the VHE regime. The study of W Comae extends from 2008 to 2014, resulting in a 6 standard deviation (σ) detection from ~40 observing hours. Analysis of 3C 66A from 2007 to 2015, totaling ~67 hours, resulted in a 17σ lower flux state detection. We will report on the results from these VHE analyses as well as contemporaneous multiwavelength data and comment on how these lower state IBL detections fit within the context of the blazar paradigm. Speaker: Dr Lucy Fortson (University of Minnesota) • 3:30 PM Naima: a Python package for inference of particle distribution properties from nonthermal spectra 1h The ultimate goal of the observation of nonthermal emission from astrophysical sources is to understand the underlying particle acceleration and evolution processes, and few tools are publicly available to infer the particle distribution properties from the observed photon spectra from X-ray to VHE gamma rays. Naima is an open source Python package that provides models for non-thermal radiative emission from homogeneous distribution of relativistic electrons and protons. Contributions from synchrotron, inverse Compton, nonthermal bremsstrahlung, and neutral-pion decay can be computed for a series of functional shapes of the particle energy distributions, with the possibility of using user-defined particle distribution functions. In addition, Naima provides a set of functions that allow to use these models to fit observed nonthermal spectra through an MCMC procedure, obtaining probability distribution functions for the particle distribution parameters. In this contribution I will present the models and methods available in Naima and an example of their application to the understanding of a galactic nonthermal source. Speaker: Victor Zabalza (University of Leicester) • 3:30 PM NectarCAM : a camera for the medium size telescopes of the Cherenkov Telescope Array 1h NectarCAM is a camera proposed for the medium-sized telescopes of the Cherenkov Telescope Array (CTA) covering the central energy range of ~100 GeV to ~30 TeV. It has a modular design and is based on the NECTAr chip, at the heart of which is a GHz sampling Switched Capacitor Array and 12-bit Analog to Digital converter. The camera will be equipped with 265 7-photomultiplier modules, covering a field of view of 8 degrees. Each module includes the photomultiplier bases, high voltage supply, pre-amplifier, trigger, readout and Ethernet transceiver. The recorded events last between a few nanoseconds and tens of nanoseconds. The camera trigger will be flexible so as to minimize the read-out dead-time of the NECTAr chips. NectarCAM can sustain a data rate of more than 4 kHz with less than 5% dead time. The camera concept, the design and tests of the various subcomponents and results of thermal and electrical prototypes are presented. The design includes the mechanical structure, cooling of the electronics, read-out, clock distribution, slow control, data-acquisition, triggering, monitoring and services. Speaker: Jean-Francois Glicenstein (CEA) • 3:30 PM New concepts of timing calibration systems for large-scale Cherenkov arrays in astroparticle physics experiments 1h We present new concepts of timing calibration systems for large-scale Cherenkov arrays in astroparticle physics experiments like Cherenkov arrays detecting extensive air showers (EAS) and water Cherenkov neutrino arrays. The concepts are based on a fast powerful LED light source on board of a pilotless remotely controlled helicopter in case of EAS Cherenkov arrays and on multiple LED sources driven by a single driver. We describe parameters of LED sources developed especially for these kinds of applications and discuss some preliminary results of laboratory and in-situ tests. Speaker: Bayarto Lubsandorzhiev (Institute for Nuclear Research of RAS) • 3:30 PM Observation of the^{26}Al$emission distribution throughout the Galaxy with INTEGRAL/SPI 1h We present$^{26}Al$map distribution throughout the Galaxy measured by the SPI spectrometer aboard the INTEGRAL observatory. This emission at 1.809 MeV is associated with the$^{26}Al$decay and to the production of heavy elements in the Galaxy. The only available$^{26}Al$map to date has been released, more than fifteen years ago, thanks to the COMPTEL instrument. However, at the present time, SPI offers a unique opportunity to enrich this first result. The data accumulated between 2003 and 2013 which amounts to 2$\times$10$^{8}$s of observing time are used to perform a dedicated analysis, aiming to deeply investigate the spatial morphology of the$^{26}Al$emission. The data are first compared with several sky maps based on observations at various wavelengths to model the$^{26}Al$distribution throughout the Galaxy. For most of the distribution models, the inner Galaxy flux is compatible with a value of 3.3$\times$10$^{-4}$ph. cm$^{-2}$.s$^{-1}$while the preferred template maps correspond to young stellar components such as core-collapse supernovae, Wolf-Rayet and massive AGB stars. To get more details about this emission, an image reconstruction is performed using an algorithm based on the maximum-entropy method. In addition to the inner Galaxy emission, several excesses suggest that some sites of emission are linked to the spiral arms structure. Lastly, an estimation of the$^{56}Fe$line flux, assuming a spatial distribution similar to$^{26}Al$line emission, results in a$^{56}Fe$to$^{26}Al$ratio around 0.14, which agrees with the most recent studies and with the SN explosion model predictions. Speaker: Dr Laurent Bouchet (IRAP) • 3:30 PM On the On-Off Problem: an Objective Bayesian Analysis 1h The On-Off problem, aka. Li-Ma problem, is a statistical problem where a measured rate is the sum of two parts. The first is due to a signal and the second due to a background, both of which are unknown. Mostly frequentist solutions are being used, but they are only adequate for high count numbers. When the events are rare such an approximation is not good enough. Indeed, in high-energy astrophysics this is often the rule, rather than the exception. I will present a universal objective Bayesian solution that depends only on the initial three parameters of the On/Off problem: the number of events in the on-source region, the number of events on the off-source region, and their ratio-of-exposure. With a two-step approach it is possible to infer the signal's significance, strength, uncertainty or upper limit in a unified a way. The approach is valid without restrictions for any count number including zero and may be widely applied in particle physics, cosmic-ray physics and high-energy astrophysics. I apply the method to gamma-ray burst data. Speaker: Max Ludwig Ahnen (ETH Zurich) • 3:30 PM Optical Polarimetry Campaign on Markarian 421 During the 2012 Large Flaring Episodes 1h n 2012, Fermi/LAT gamma-ray and radio observations have registered the largest ever recorded flaring episodes from the blazar Markarian 421. The unprecedented activity state of the source has remained high, and much above the normal behaviour seem from the source also for the year 2013, characterising a dramatic and long-lasting change of behaviour in the emission of the object. This unique event has been followed, and showed extreme signatures in all bands in which it was observed, from radio to VHE gamma-rays. Polarisation monitoring of the source has nevertheless been somewhat more scarce, and direct observation of the peak activity in 2012 was prevented by the source's proximity with the Sun at the time. As part of our continuous monitoring programme of TeV emitting blazars in optical polarimetry at the Liverpool Telescope, whose first phase used the RINGO2 fast polarimeter and lasted from late 2010 to early 2013, we have observed Mkn 421 with regular coverage and a sub-weekly cadence for over two years. This continued monitoring allowed us to follow the polarisation behaviour of the source for over two years and up to the days preceding the dramatic flare event in 2012. In the weeks before the multi-wavelength and high-energy outbursts, Mrk 421 presented an unprecedented increase in its degree of polarisation, which rose by a factor of 5, not witnessed in decades from this object. The source also showed a never-seen large rotation of its polarisation angle, by over 180 degrees. In this talk we will present our entire dataset on Mkn 421 , concentrating in discussing the unprecedented events in optical polarisation that preceded the HE outburst. The main question we put ourselves is if what we have seen is a polarimetric precursor of the high activity that followed. If yes, what connections can we establish between them, and what remains mysterious to us about it? Speaker: Ulisses Barres (Centro Brasileiro de Pesquisas Físicas) • 3:30 PM Performance of the Mechanical Structure of the SST-2M GCT Telescope for the Cherenkov Telescope Array 1h The Cherenkov Telescope Array (CTA) project aims to create the next generation Very High Energy gamma-ray telescope array. It will be devoted to the observation of gamma rays over a wide band of energy, from 20 GeV to 300 TeV. Two sites are foreseen, one in the northern and the other in the southern hemisphere, allowing the viewing of the whole sky. The southern site will be equipped with about 100 telescopes, composed of three different classes, Large, Medium and Small Size Telescopes, covering the low, intermediate and high energy regions, respectively. The energy range of the Small Size Telescopes (SSTs) extends from 1 TeV to 300 TeV. Among them, the Gamma-ray Cherenkov Telescope (GCT), a telescope based on a Schwarzschild-Couder dual-mirror optical formula, is one of the prototypes under construction proposed to be part of the southern site of the future Cherenkov Telescope Array. This contribution focuses on the mechanical structure of this telescope. It presents the mechanical design and discusses how this in the context of CTA specifications. It also describes recent developments in the assembly and installation of the opto-mechanical prototype of GCT on the French site of the Paris Observatory. Speaker: Dr Jean-Laurent Dournaux (GEPI. CNRS, Observatoire de Paris) • 3:30 PM Performance studies of the new stereoscopic Sum-Trigger-II of MAGIC after one year of operation 1h MAGIC is a stereoscopic system of two Imaging Air Cherenkov Telescopes (IACTs) located at La Palma (Canary Islands, Spain) and working in the field of very high energy gamma-ray astronomy. It makes use of a traditional digital trigger with an energy threshold of around 55 GeV. A novel trigger strategy, based on the analogue sum of signals from partially overlapped patches of pixels, leads to a lower threshold. In 2008, this principle was proven by the detection of the Crab Pulsar at 25 GeV by MAGIC in single telescope operation. During Winter 2013/14, a new system, based on this concept, was implemented for stereoscopic observations after several years of development. In this contribution the strategy of the operative stereoscopic trigger system, as well as the first performance studies, are presented. Finally, some possible future improvements to further reduce the energy threshold of this trigger are addressed. Speaker: Dr Francesco Dazzi (Max-Planck-Institute for Physics Munich) • 3:30 PM Photon Reconstruction for H.E.S.S. Using a Semi-Analytical Model 1h The High Energy Stereoscopic System (H.E.S.S.) is an array of five Imaging Atmospheric Cherenkov Telescopes (IACTs) designed to detect and image cosmogenic gamma-rays with very high energies. Originally consisting of just four identical IACTs (CT1-4) with an effective mirror diameter of 12$\,$m each, it was expanded with a fifth IACT (CT5) with a mirror diameter of 28$\,$m in 2012. Being the largest IACT worldwide, CT5 allows to lower the energy threshold of H.E.S.S., enabling to close the energy gap between space-based detectors and IACTs. Events can be analysed either monoscopically (i.e. using only information of CT5) or stereoscopically (requiring at least two triggered telescopes per event). To achieve a good performance, a sophisticated event reconstruction and analysis framework is indispensable. This is particularly important for H.E.S.S. since it is now the first IACT array that consists of different telescope types. An advanced reconstruction method is based on a semi-analytical model of electromagnetic particle showers in the atmosphere ("model analysis"). The properties of the primary particle are reconstructed by comparing the image recorded by each triggered telescope with the Cherenkov emission from the shower model using a log-likelihood maximisation. Due to its performance, this method has become one of the standard analysis techniques applied to CT1-4 data. Now it has been modified for use with the five-telescope array. We present the adapted model analysis and its performance in both monoscopic and stereoscopic analysis mode. Speaker: Markus Holler (LLR - Ecole Polytechnique) • 3:30 PM Progress on the electromagnetic particle detector and the prototype array of LHAASO-KM2A 1h A prototype array for the LHAASO-KM2A, which consists of 39 detector units, was set up at the Yangbajing cosmic ray observatory(4300m a.s.l., Tibet, P.R. China) and has been in stable operation since Octoter 2014. In this paper, we present the performances of the prototype electromagnetic particle detector and the prototype array. Speaker: Sun Zhandong (Southwest Jiaotong University) • 3:30 PM Rapid variability at very high energies in Mrk 501 1h Flaring states of the BL Lac object, Mrk 501 were observed by the High Energy Stereoscopic System (H.E.S.S.) during 2012 and 2014. Observations in 2014 recorded flux levels higher than one Crab unit and revealed rapid variability at very high energies ($\sim$2-20 TeV). The high statistics afforded by the flares allowed us to probe the presence of minutes timescale variability and study its statistical characteristics at purely TeV energies owing to the high threshold energy of approximately 2 TeV. Doubling times of a few minutes are estimated for fluxes, F(> 2 TeV). Statistical tests on the lightcurves show interesting temporal structure in the variations including deviations from a normal flux distribution similar to those found in the PKS 2155-⁠304 flare of July 2006, at nearly an order of magnitude higher threshold energy. Rapid variations at such high energies put strong constraints on the physical mechanisms in the blazar jet. Speaker: Dr Nachiketa Chakraborty (Max-Planck-Institut fuer Kernphysik) • 3:30 PM Recent pulsar results from VERITAS on Geminga and the missing link binary pulsar PSR J1023+0038 1h In recent years, the Fermi-LAT gamma-ray telescope has detected a population of over 160 gamma-ray pulsars, which has enabled the detailed study of gamma-ray emission from pulsars at energies above 100 MeV. Further, since the surprising detection of the Crab pulsar in very high-energy (VHE; E > 100 GeV) gamma rays by the MAGIC and VERITAS collaborations, there has been an ongoing effort in the gamma-ray astrophysics community to detect new pulsars in the VHE band. However, the Crab remains the only pulsar so far detected in VHE gamma rays, raising the question of whether or not the Crab is unique and also making it more difficult to constrain model predictions that attempt to explain the VHE emission. Presented here are recent VERITAS results from observational campaigns on the brightest northern-hemisphere high-energy gamma-ray pulsar Geminga and the missing link binary pulsar PSR J1023+0038, which have both resulted in upper limits on a possible gamma-ray flux. These limits are placed into context with the current theoretical framework attempting to explain the origin of VHE gamma-ray emission from pulsars. Additionally, future plans for pulsar observations with VERITAS will be briefly discussed. Speaker: Gregory Richards (Georgia Institute of Technology) • 3:30 PM Redshift measurement of Fermi Blazars for the Cherenkov Telescope Array 1h Blazars are active galactic nuclei, and the most numerous High Energy (HE) and Very High Energy (VHE)gamma-ray emitters. Their optical emission is often dominated by non-thermal, and, in the case of BL Lacs, featureless continuum radiation. This renders the determination of their redshift extremely difficult. Indeed as of today only about 50% of gamma-ray blazars have a measured spectroscopic redshift. The knowledge of redshift is fundamental because it allows the precise modeling of the VHE emission and also of its interaction with the extragalactic background light (EBL). The beginning of the Cherenkov Telescope Array (CTA) operations in the near future will allow detecting several hundreds of new BL Lacs. Using the first Fermi catalogue of sources above 10 GeV (1FHL), we performed simulations which demonstrate that at least half of the 1FHL BL Lacs detectable by CTA will not have a measured redshift. Indeed the organization of observing campaigns to measure the redshift of these blazars has been recognized as a necessary support for the AGN Key Science Project of CTA. Taking advantage of the recent success of an X-shooter GTO observing campaign, we thus devised an observing campaign to measure the redshifts of as many as possible of these candidates. The main characteristic of this campaign with respect to previous ones will be the use of higher resolution spectrographs and of 8 meter class telescopes. We are starting submitting proposals for our observations. In this paper we will briefly describe the selection of the candidates, the characteristics of our observation and the expected results. Speaker: Dr Paolo Goldoni (APC/CEA-Irfu) • 3:30 PM ROI: A Prototype Data Model for the Cherenkov Telescope Array 1h The Cherenkov Telescope Array (CTA) will be a ground-based gamma-ray observatory with full-sky coverage in the very-high energy (VHE) regime. It is proposed to consist of more than 100 telescopes and should produce large amounts of data, possibly exceeding the volume of current VHE Imaging Atmospheric Cherenkov Telescopes by ~two orders of magnitude. This volume of data represents a new challenge to the VHE community, which is looking for new data formats to transfer and store the CTA data. One of the prototypes currently under study is the ROI (Regions Of Interest) file format for camera images. It stores only those pixels of a camera image that are close to the shower, thus removing the major part of the night sky background while keeping all pixels that might belong to the shower. Simple, on-the-fly compression is used to reduce the file size even further. Here, we explain the ROI prototype in detail and present preliminary results applied to real data and simulations. Speaker: Mr Ramin Marx (MPIK Heidelberg) • 3:30 PM Search for Gamma-ray Production in Supernovae located in a dense interstellar medium with Fermi LAT 1h Supernovae (SNe) exploding in a dense circumstellar medium (CSM) are hypothesized to accelerate cosmic rays in collisionless shocks and emit GeV gamma rays and TeV neutrinos on a time scale of several months. We perform the first systematic search for gamma-ray emission in Fermi LAT data in the energy range from 100 MeV to 300 GeV from the ensemble of SNe exploding in dense CSM. We study a sample of 147 SNe Type IIn and search for a gamma-ray excess at each SNe location using the maximum likelihood method for each source in a one year time window. In order to enhance a possible weak signal, we simultaneously study the closest and optically brightest sources of our sample in a joint likelihood analysis in three different time windows (1 year, 6 months and 3 months). We do not find a significant excess in gamma rays for any individual source nor for the combined sources and provide flux upper limits at 95% confidence level (CL) for both cases. We calculate model independent limits on the gamma-ray flux for individual sources as well as the combined source sample. In addition, we derive limits on the gamma-ray luminosity and the ratio of gamma-ray to optical luminosity as a function of the index of the proton injection spectrum assuming a generic gamma-ray production model. Speaker: Anna Franckowiak (SLAC) • 3:30 PM Search for VHE gamma-ray emission from the Geminga pulsar and nebula with the MAGIC telescopes 1h Geminga pulsar appears to be one of the most promising candidates to emit VHE gamma-ray pulsed emission. In order to detect the third pulsar with power-law spectral component above of the measured cutoff, after Crab and Vela, we analyzed 63 hours of data taken with MAGIC. To discuss the connection with HE gamma rays, 6 years of Fermi-LAT data were also analyzed. No significant pulsation was found with MAGIC observations. The obtained flux upper limits above 50 GeV are above the power law extrapolation above 10 GeV based on Fermi-LAT data. We also searched for steady emission from the pulsar wind nebula in the same dataset, resulting in no significant detection. Speaker: marcos lopez (University Complutense of Madrid) • 3:30 PM Selection of AGN to study the extragalactic background light with HAWC 1h The extragalactic background light (EBL) is all the electromagnetic energy released by resolved and unresolved extragalactic sources since the recombination era. Its intensity and spectral shape provide information about the evolution of galaxies throughout cosmic history. Since direct observations of the EBL are very difficult to perform, the study of the interaction between the low energy EBL photons and high energy photons from distant sources becomes relevant to constrain the EBL intensity. The main goal of this study is to investigate the opacity of the EBL to gamma rays by observing a sample of active galaxies with the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory. Current gamma-ray observations up to 20 TeV performed by Imaging Atmospheric Cherenkov Telescopes (IACTs) have constrained the EBL intensity in the$0.1-50\mu$m region. HAWC which monitors the gamma-ray sky in the 100 GeV to 100 TeV energy range, will be able to detect at least 12 active galaxies at redshifts below 0.3 and thus constrain the EBL in the poorly-measured$1-100\mu$m region. Speaker: Mrs Sara Coutiño (INAOE) • 3:30 PM Sensitivity of the LHAASO-WCDA for various Gamma ray sources 1h The Large High Altitude Air Shower Observatory (LHAASO) will be constructed at Mt. Haizi in Sichuan Provice, China. As a major component of the LHAASO project, the Water Cherenkov Detector Array (WCDA) is designed to record air showers produced by cosmic rays and gamma rays in the energy range from 100 GeV to 100 TeV. Complementing the Imaging Atmospheric Cherenkov Telescopes with large field-of-view and long duty cycle, and the space-based gamma-ray detectors with high energy reach, WCDA is well-suited to study particle acceleration in Pulsar Wind Nebulae, Supernova Remnants, Active Galactic Nuclei and Gamma-ray Bursts. Results of the sensitivity calculation of the detector on steady point sources, extended sources, transient sources and GRBs are presented in this talk. Speakers: Dr Bo Gao (Institute of High Energy Physics,CAS), Dr Hanrong Wu (Institute of High Energy Physics,CAS), Mr Huicai Li (Naikai University), Dr Mingjun Chen (Institute of High Energy Physics,CAS), Prof. Zhiguo Yao (Institute of High Energy Physics,CAS) • 3:30 PM Shaping the GeV-spectra of bright blazars 1h The non-thermal spectra of jetted Active Galactic Nuclei (AGN) show a variety of shapes and degrees of curvature in their low and high energy components. From some of the brightest Fermi-LAT blazars prominent spectral breaks at a few GeV have been regularly detected which is inconsistent with conventional cooling effects. We propose that the broad variety of spectral shapes including prominent breaks can be understood as an impact of injection modes. We therefore present an injection model embedded in a leptonic blazar emission model for external Comptonloss dominated jets of AGN which aims towards bridging jet emission with acceleration models using a phenomenological approach. In our setup we consider the effects of continuous time-dependent injection of electrons into the jet with differing rates, durations, locations and power-law spectral indices, and evaluate its impact on the ambient emitting particle spectrum observed at a given snapshot time. We found that varying the injection parameters has indeed notable influence on the spectral shapes, which in turn can be used to set interesting constraints on the particle injection scenario. We apply our model to the flare state spectral energy distribution of 3C 454.3 and PKS 1510-089 to constrain the required injection parameters. Our results indicate that impulsive-like particle injection is disfavored here. With this model we provide a basis for analyzing ambient electron spectra in terms of injection requirements, with implications for particle acceleration modes. Speaker: Anita Reimer (University of Innsbruck) • 3:30 PM Simulation of diffusive particle propagation and related TeV$\gamma$-ray emission at the Galactic Center 1h Observations of the Galactic Center with the H.E.S.S. instrument have led to the detection of an extended region of diffuse TeV$\gamma$-ray emission. The origin of this emission is not yet fully understood, although the spatial correlation between the density distribution of giant molecular clouds located at the center of our Galaxy and the intensity of the observed$\gamma$-ray excess points towards a hadronic production scenario. The energy amount required to accelerate charged hadrons producing a$\gamma$-ray emission as observed could have been delivered by a single supernova explosion. Assuming that highly energetic particles have been released by a single central source, we analyzed if the diffusion of relativistic hadrons is fast enough to produce an extended TeV emission through interactions with ambient matter as observed. We numerically analyzed charged-particle motion in turbulent magnetic fields with regard to the environmental conditions of the Galactic Center region. We present diffusion coefficients derived from a statistical analysis of the tracking of ensembles of particles in such a turbulent environment. The derived diffusion coefficients were used to simulate the diffuse$\gamma$-ray emission from the Galactic Center region via a discretization of the diffusion equation. The results of this modeling are presented and compared to the H.E.S.S. measurement, including both spectral and morphological analysis. Speaker: Alexander Ziegler (ECAP, University of Erlangen-Nuremberg, Germany) • 3:30 PM Simulation study on a large field of view cherenkov telescope 1h The large field of view and low threshold energy are highly desirable properties for the ground based observations of high energy GRBs. However, larger field of view is difficult to achieve for current imaging atmospheric cherenkov telescopes (IACT), and the threshold below O(100)GeV is also a challenging for current EAS arrays. An alternative solution is to adopt the refractive optics system for IACTs to enlarge the field of view while keeping the low threshold energy. In this work, simulation studies on the effective area, angular resolution and gamma-ray sensitivity for such large field of view IACT are presented. Speaker: Dr Yi Zhang (IHEP) • 3:30 PM Status and plans for the Array Control and Data Acquisition System of the Cherenkov Telescope Array 1h The Cherenkov Telescope Array (CTA) is the next-generation atmospheric Cherenkov gamma-ray observatory. CTA will consist of two installations, one in each hemisphere, containing tens of telescopes of different sizes. The CTA performance requirements and the inherent complexity associated with the operation, control and monitoring of such a large distributed multi-telescope array leads to new challenges in the field of the gamma-ray astronomy. The ACTL (array control and data acquisition) system will consist of the hardware and software that is necessary to control and monitor the CTA array, as well as to time-stamp, read-out, filter and store -at aggregated rates of few GB/s- the scientific data. The ACTL system must be flexible enough to permit the simultaneous automatic operation of multiple sub-arrays of telescopes with a minimum personnel effort on site. One of the challenges of the system is to provide a reliable integration of the control of a large and heterogeneous set of devices. Moreover, the system is required to be ready to adapt the observation schedule, on timescales of a few tens of seconds, to account for changing environmental conditions or to prioritize incoming scientific alerts from time-critical transient phenomena as gamma ray bursts. This contribution provides a summary of the main design choices and plans for building the ACTL system. Speaker: Igor Oya (DESY Zeuthen) • 3:30 PM Status of Water Cerenkov Detector Array of LHAASO project 1h A Large High Altitude Air Shower Observatory (LHAASO) is planned to be built in next year. As an important component of LHAASO project, Water Cherenkov Detector Array (WCDA) is a high sensitivity gamma ray and cosmic ray detector, which is mainly to survey the northern sky for VHE gamma ray sources. Currently, the R&D is quite finished, including a prototype water Cherenkov detector and an engineering array at 1% scale (3×3 cells). In this paper, the basic design, performance and R&D work of WCDA will be described. Speakers: Bo Gao (Institute of High Energy Physics, Chinese Academy of Sciences), Dr Mingjun Chen (Institute of High Energy Physics, Chinese Academy of Sciences) • 3:30 PM Study of the VHE diffuse emission in the central 200 pc of our Galaxy with H.E.S.S. 1h The Very High Energy Galactic Center Ridge was revealed by H.E.S.S. in 2006, after subtraction of the point sources HESS J1745-290 possibly associated with Sgr A* and HESS J1747-281 associated with the composite supernova remnant G0.09+0.1. The hard spectrum of the Ridge emission and its spatial correlation with the local gas density suggest that the emission is due to collisions of multi-TeV cosmic rays with the dense clouds of interstellar gas present in this region. The much larger H.E.S.S. dataset (250 hrs) that is now available from this region and the improved analysis method dedicated to faint emission allow us to reconsider the characterization of this gamma-ray emission in the central 200 pc of our Galaxy through a detailed morphology study and the exctraction of the total energy spectrum with much better accuracy. To test the various contributions to the total gamma-ray emission, we use a 2D maximum likelihood approach that allows to constrain a phenomenological model of the signal.We discuss the nature of the various components, and their implication on the cosmic-ray distribution in the central 200 pc of our Galaxy. Finally, we will reveal an additional source in this region and will discuss its potential nature. Speaker: Dr Anne Lemière (APC) • 3:30 PM Study on the large dimensional refractive lens for the future large field-of-view IACT 1h Sub-100GeV to TeV is a crucial energy window in gamma ray astronomy because of its important role connecting the space experiments and the ground-based observations. The observations in this energy range are expected to provide rich information about the high energy emission from GRBs and AGNs, with which EBL can be measured, and knowledge about the galaxy formation and the evolution of the early universe can be obtained. One pursuit of the next generation Imaging Atmospheric Cherenkov Telescopes (IACT) is to achieve larger field of view by using a refractive optics system as light collector. In this work, preliminary test results on the optical properties (transmittance, angular resolution, etc.) of a prototype 0.9m diameter water lens are presented and discussed. Speakers: Prof. Luobu Danzeng (Tibet University), Prof. Tianlu Chen (Tibet University) • 3:30 PM Systematically characterizing regions of the First Fermi-LAT SNR Catalog 1h While supernova remnants (SNRs) are widely thought to be powerful cosmic-ray accelerators, indirect evidence comes from a small number of well-studied cases. Here we systematically determine the gamma-ray emission detected by the Fermi Large Area Telescope (LAT) from all known Galactic SNRs, disentangling them from the sea of cosmic-ray generated photons in the Galactic plane. Using LAT data we have characterized the 1-100 GeV emission in 279 regions containing SNRs, accounting for systematic uncertainties caused by source confusion and instrumental response. We have also developed a method to explore some systematic effects on SNR properties caused by the modeling of the interstellar emission (IEM). The IEM contributes substantially to gamma-ray emission in the regions where SNRs are located. To explore the systematics we consider different model construction methods, different model input parameters, and independently fit the model components to the gamma-ray data. We will describe this analysis method in detail. In the First Fermi-LAT SNR Catalog there are 30 sources classified as SNRs, using spatial overlap with the radio position. For all the remaining regions we evaluated upper limits on SNRs' emission. In this work we will present a study of the aggregate characteristics of SNRs, such as comparisons between GeV and radio sizes as well as fluxes and spectral indexes and with TeV. Speaker: Dr Francesco de Palma (INFN and Pegaso University) • 3:30 PM TAIGA experiment – status, first results and perspectives 1h The aim of the TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy) is to construct in the Tunka Valley (50 km from Lake Baikal) a complex, hybrid array for multi–TeV gamma-ray astronomy and CR studies. The array will consist of a wide angle Cherenkov array - Tunka-HiSCORE with ~3 km2 area, a net of IACT telescopes and muon detectors with total area of up to 2000 m2. We present the current status of the array construction, sensitivity to local sources of gamma-rays and first results from operation of the array prototype. Speaker: Prof. Leonid Kuzmichev (SINP MSU) • 3:30 PM TeV gamma-rays from the globular cluster NGC 6624 containing energetic millisecond pulsar J1823-3021A 1h Recently very energetic millisecond pulsar, J1823-3021A, has been discovered to emit pulsed GeV gamma-rays in the globular cluster NGC 6624. Assuming that this pulsar injects relativisitic leptons into its surrounding (as expected from modelling of radiative processes within the inner pulsar magnetosphere), we calculate the minimum level of expected TeV gamma-ray emission produced by these leptons in the Inverse Compton scaterring process of stellar radiation from the globular cluster NGC 6624. The results of calculations are confronted with sensitivities of the present and future Cherenkov telescopes. Speaker: Wlodek Bednarek (University of Lodz) • 3:30 PM The first GCT camera for the Cherenkov Telescope Array. 1h The Gamma-ray Cherenkov Telescope (GCT) is proposed to be part of the Small Size Telescope (SST) array of CTA (the Cherenkov Telescope Array). Its dual mirror optical design allows the use of a compact camera of diameter roughly 0.4m, the curved focal plane of which is equipped with 2048 pixels of ~0.2° angular size, resulting in a field of view of ~9°. The GCT camera is designed to record the flashes of Cherenkov light from gamma-ray initiated electromagnetic cascades, which last only a few tens of nanoseconds. Modules based on “TARGET” ASICs provide the required fast electronics, allowing sampling at 1 GSample/s and digitization, as well as first level of triggering using the analogue outputs of the photosensors. The GCT camera is the first fully assembled prototype for a dual mirror Cherenkov telescope ever built and is currently being commissioned in the UK. On-telescope testing of its performance is expected to take place in France in September 2015. In this paper we give a detailed description of the mechanics and electronics of the camera and discuss recent progress with testing and commissioning. Speaker: Andrea De Franco (University of Oxford) • 3:30 PM The FRaNKIE code: a tool for calculating multi-wavelength interstellar emissions in galaxies 1h The Fast Radiation transport Numerical Kalculation for Interstellar Emission (FRaNKIE) code is a Monte Carlo code for calculating the electromagnetic emissions in galaxies. The code is highly parallel and optimised for both CPUs and co-processor accelerators. The code takes into account the interaction of the photon field with the interstellar medium in a self-consistent way, providing a detailed model for the interstellar radiation field. I will describe the implementation details of the code and present results of its application to the problem of calculating the interstellar radiation field of the Milky Way. The radiation field is an essential input to CR propagation codes for calculating the cosmic-ray lepton energy losses from inverse Compton scattering and the resulting gamma-ray emission. Speaker: Dr Troy Porter (Stanford University) • 3:30 PM The H.E.S.S. multi-messenger program 1h Based on fundamental particle physics processes like the production and subsequent decay of pions in interactions of high-energy particles, close connections exist between the acceleration sites of high-energy cosmic rays and the emission of high-energy gamma rays, high-energy neutrinos and other messengers like gravitational waves. In most cases these connections provide both spatial and temporal correlations of the different emitted particles. The combination of the complementary information provided by these messengers allows to lift ambiguities in the interpretation of the data and enables novel and very sensitive analyses. In this contribution we'll introduce and describe the H.E.S.S. multi-messenger program. The core of this newly installed program is the combination of high-energy neutrinos and high-energy gamma rays. We’ll furthermore present searches for high-energy gamma-ray emission in coincidence with Fast Radio Bursts (FRBs) and gravitational waves. We'll provide an overview over current and planned analyses and present recent results. Speaker: Dr Fabian Schüssler (Irfu, CEA-Saclay) • 3:30 PM The measurement of the expansion rate of the Universe from gamma-ray attenuation 1h The extragalactic background light (EBL) contains fundamental cosmological and galaxy evolution information. Very high energy observations of extragalactic sources, such as blazars, can be used to extract this information because of the pair-production interaction between gamma-ray and EBL photons. We present (almost) simultaneous broad-band data of a dozen BL Lacs that allow us to make the first statistically significant detection of the cosmic gamma-ray horizon (CGRH), which is a measure of how far gamma-ray photons of different energies can travel through the Universe due to EBL attenuation. From a comparison of our CGRH detection with an EBL model built from multiwavelength data taken with deep galaxy surveys, we conclude that there is no a significant amount of light escaping to galaxy surveys, at least, in the low redshift Universe. This CGRH detection also allow us to present an independent and novel technique aimed at measuring the expansion rate of the Universe from gamma-ray observations. Speaker: Dr Alberto Dominguez (Clemson University) • 3:30 PM The stereo Topo-trigger: a new concept of stereoscopic trigger system for imaging atmospheric Cherenkov telescopes 1h Imaging atmospheric Cherenkov telescopes such as the MAGIC telescopes are built to achieve the lowest possible energy threshold. The trigger system of these telescopes is one of the most important parts to achieve it. The main problem when decreasing the energy triggered by an IACT is the rapid increase of accidental triggers caused by the ambient light and the after pulses of the photomultipliers. The coincidence trigger between the telescopes strongly suppresses the accidental rate recorded by the telescope. At lower trigger threshold, however, it is difficult to discriminate at the trigger level between the triggers produced by accidental triggers or real cosmic events. In this contribution we present a topological trigger, dubbed Topo-trigger, a novel technique that discriminates between the events triggered by cosmic rays and accidental triggers allows a decrease of up to 85 % of the accidental events triggering MAGIC system in stereo. We have simulated and tested this algorithm in the MAGIC telescope while keeping more than 99 % of the gamma rays triggered. According to simulations, this trigger system increases the collection area at the analysis level of about 30 % at the lowest energies and between 10-20 % at the energy threshold. The decrease in the analysis energy threshold of the telescope is ~8 %. The selection algorithm proposed here was tested on real MAGIC data taken with the current trigger configuration and we find that no triggers are lost due to the algorithm proposed. A full implementation of the Topo-trigger was installed in MAGIC at the end of 2014 and the first results of its performance will also be shown. Speaker: Ruben Lopez-Coto (Institut de Fisica d'Altes Energies - IFAE) • 3:30 PM The TIBET AS+MD Project; progress report 2015 1h We plan to build a large (approximately 10,000 m**2) water Cherenkov- type muon detector array under the existing Tibet air shower array at 4,300 m above sea level, to observe 10-1000 TeV gamma rays from cosmic-ray accelerators in our Galaxy with wide field of view at very low background level. A gamma-ray induced air shower has significantly less muons compared with a cosmic-ray induced one. Therefore, we can effectively discriminate between primary gamma rays and cosmic-ray background events by means of counting number of muons in an air shower event by the muon detector array. We will make a progress report on the project, as some part of it started data-taking in 2014. Speaker: Dr Masato TAKITA (Institute for Cosmic Ray Research, the University of Tokyo) • 3:30 PM The VHE gamma-ray periodicity of PG1553+113: a possible probe of a system of binary supermassive black hole 1h The blazar PG1553+113 is an active galaxy with uncertain redshift detected at very high energies (VHE; E > 100 GeV) both during high and quiescent states. We have observed with the MAGIC telescopes from La Palma PG 1553+113 at VHE since 2005, making this blazar one of the best studied MAGIC sources. Recently, the Fermi/LAT collaboration has reported the detection of a hint of a ~2-year periodicity in the integral flux emitted by the source both at high energy gamma rays (E>100 MeV) and at optical wavelengths. Remarkably, this periodicity, if confirmed, might be interpreted as an evidence of the presence of a binary supermassive black hole system in the nucleus of PG1553+113. In this contribution, we present the result of our analysis of 10 years of PG 1553+113 MAGIC data. In particular, we test the hypothesis of a periodic modulation of the overall emitted flux at VHE, search for evidences of correlation with the emission detected at other wavelengths, and critically discuss our findings in the framework of the binary supermassive black hole model. Speaker: Elisa Prandini (University of Geneva) • 3:30 PM Time calibration for the LHAASO-WCDA project 1h As a major component of the LHAASO project, the main physical goal of the Water Cherenkov Detector Array (WCDA) is to survey the northen sky for VHE gamma ray sources. One of the key issues to fulfill this goal is the angular resolution and the pointing precision of the detector, which depends much on the time calibration of the whole array. In this paper, a new time calibration technique based on LED and plastic fibers is introduced. The test results of a prototype system of one cluster consisting of 40 fibers show that a precision of 0.1 ns, which meets the requirement of the experiment, can be achieved. This technique has some advantages such as robustness, scalability and cost effectiveness, so that having a great application potential to some other large area air shower experiments. Speakers: Dr Bo Gao (Institute of High Energy Physics, Chinese Academy of Sciences), Dr Hanrong Wu (Institute of High Energy Physics, Chinese Academy of Sciences), Mr Huicai Li (School of Physics, Nankai University), Dr Mingjun Chen (Institute of High Energy Physics, Chinese Academy of Sciences), Ms Xiaojie Wang (Institute of High Energy Physics, Chinese Academy of Sciences), Prof. Zhiguo Yao (Institute of High Energy Physics, Chinese Academy of Sciences) • 3:30 PM Time-dependent injection as a model for rapid blazar flares 1h The detection of very rapid flares on the order of minutes in blazars has spawned a lot of theoretical activity. Even though many models take time-dependent effects (such as varying magnetic fields, etc) into account, a time-dependent nature of the injection process is usually omitted. In this presentation it is shown using the standard one-zone model that time-dependent injection has strong effects on the resulting spectra of blazars. Due to the time-dependency of the injection the particles cannot reach an equilibrium state and the kinetic equation for the electron distribution function becomes non-linear. This leads to (i) much faster electron cooling and (ii) a change in the cooling process after some time depending on the injection parameters. This change in the cooling process has direct and very significant effects for the spectrum of a flaring blazar. Speaker: Michael Zacharias • 3:30 PM Triggerless scheme and trigger pattern of the LHAASO-WCDA project 1h The Water Cherenkov Detector Array (WCDA) of the LHAASO project is to be built in Daocheng, Sichuan Province of China. It comprises of 4 neighboring ponds, each in dimension of 150 m$\times$150 m, and divided into 900 cells, with a PMT in each cell. A triggerless scheme is to be adopted for the data acquiring system, in which all the single channel signals are synchronized and transferred to an online computing cluster, to build into events based on a dedicated trigger pattern. The trigger pattern is introduced in this paper. The feature of the trigger pattern is noise tolerance and scalability, and it can be generalized for some other air shower experiments. Speakers: Dr Bo Gao (IHEP, Beijing), Dr Hanrong Wu (IHEP, Beijing), Mr Huicai Li (School of Physics, Univeristy of Nankai), Dr Mingjun Chen (IHEP, Beijing), Ms Xiaojie Wang (IHEP, Beijing), Prof. Zhiguo Yao (IHEP, Beijing) • 3:30 PM Updated results from VERITAS on the Crab pulsar 1h The Crab pulsar and plerion are some of the brightest and best studied non-thermal astrophysical sources. The recent discovery of pulsed gamma-ray emission above 100 GeV from the Crab pulsar with VERITAS (the Very Energetic Radiation Imaging Telescope Array System) challenges commonly accepted pulsar emission models and puts the gamma-ray emission region far out in the magnetosphere – close to or even beyond the light cylinder. We present updated VERITAS results from the analysis of a data set that is twice the original data set published in 2011. The results are discussed in the context of discriminating between different models put forward to explain gamma-ray emission mechanisms and acceleration regions within the Crab pulsar's magnetosphere. Speaker: Thanh Nguyen • 3:30 PM Upper limits on diffuse gamma-rays measured with KASCADE-Grande 1h KASCADE-Grande was a multi-detector array to measure individual air showers of cosmic rays in the energy range of 10 PeV up to 1 EeV. Based on full data sets measured by KASCADE-Grande, an upper limit to the flux of ultra-high energy gamma rays in primary cosmic rays is determined. The analysis is performed by selecting air showers with low muon contents due to a small fraction of secondary hadrons in gamma ray showers with respect to hadronically induced cosmic ray showers. A preliminary result on the 90% C.L. upper limit to the relative intensity of gamma-ray induced showers with respect to all cosmic-ray primaries will be presented, and discussed with limits reported in previous measurements. Speaker: Dr Donghwa Kang (Karlsruhe Institute of Technology) • 3:30 PM Upper limits on the VHE$\gamma$-ray flux from the ULIRG Arp 220 and other galaxies with VERITAS 1h The cores of Ultra-Luminous InfraRed Galaxies (ULIRGs) are very dense environments, with a high rate of star formation and hence supernova explosions. They are thought to be sites of cosmic-ray acceleration, and are predicted to emit$\gamma$-rays in the GeV to TeV range. So far, no ULIRG has been detected in$\gamma$-rays. Arp 220, the closest ULIRG to Earth, has been well studied, and detailed models of$\gamma$-ray production inside this galaxy have been derived. They predict a rather hard$\gamma$-ray spectrum up to several TeV. Due to its large rate of star formation, high gas density, and its close proximity to Earth, Arp 220 is thought to be a very good candidate for observations in very-high-energy (VHE, above 100 GeV)$\gamma$-rays. Arp 220 was observed by the VERITAS telescopes for more than 30 hours with no significant excess over the cosmic-ray background. The upper limits on the VHE$\gamma\$-ray flux of Arp 220 derived from these observations are the most sensitive limits presented so far and are starting to constrain theoretical models. The observations of Arp 220 are compared to the VERITAS flux limits derived for other galaxies.
Speaker: Henrike Fleischhack (DESY)
• 3:30 PM
VERITAS Discovery of Very High-Energy Gamma-Ray Emission from RGB J2243+203 1h
In this talk, we report the VERITAS discovery of very high energy (E > 100 GeV) gamma ray emission from RGB J2243+204, previously detected in radio and X-ray. This source is also consistent with the Fermi-LAT gamma-ray source 1FHL J2244.0+2020. RGB J2243+204 has been classified both as an intermediate-frequency-peaked BL Lac object and as a high-frequency-peaked BL Lac object in the past. Despite displaying a featureless spectrum, the source distance has been constrained through optical imaging, allowing the redshift of the source to be estimated at greater than 0.39. The source was detected by VERITAS at a statistical significance > 5.7 sigma with 4 hours of VERITAS exposure between 21 Dec 2014 and 24 Dec 2014 (UT). A preliminary flux estimate of ~4% Crab above 180 GeV was previously announced in ATel #6849 (24 Dec 2014). In this talk, the complete VERITAS observations, analysis, and spectral results of RGB J2243+204 will be summarized. Quasi-simultaneous observations with VERITAS, Fermi-LAT and Swift XRT will also be presented.
Speaker: David Kieda (University of Utah)
• 3:30 PM
VERITAS long-term (2006-2014) observations of the BL Lac object 1ES 0806+524 1h
The high-frequency-peaked BL Lac object 1ES 0806+524 (z=0.138) was discovered as a source of very-high-energy (VHE, E>100 GeV) gamma-ray photons in 2008 with the VERITAS telescope array, at a level of 1.8% of the Crab Nebula flux above 300 GeV. Since then, VERITAS has continued observing the source over multiple seasons, significantly improving the significance of the detection. We report the results of the analysis of the 2006-2014 VERITAS data, corresponding to a total exposure of about 80 hours. We present the new, average VHE spectrum of the source, together with the multi-year light-curve constraining long-term VHE variability.
Speaker: Matteo Cerruti (Harvard-Smithsonian Center for Astrophysics)
• 3:30 PM
VERITAS Observations of HESS J1943+213 1h
HESS J1943+213 is a very-high-energy (VHE; > 100 GeV) gamma-ray point source detected during the H.E.S.S. Galactic Plane Survey. Radio, infrared, X-ray, and GeV gamma-ray counterparts have been identified for HESS J1943+213; however, the classification of the source is still uncertain. Recent publications have argued primarily in favor of either an extreme BL Lac object behind the Galactic plane or a young pulsar wind nebula. We present deep VERITAS observations of HESS J1943+213, which provide the most significant VHE detection of the source so far, with >20 sigma excess. The source is detected at ~2% Crab Nebula flux above 200 GeV, consistent with the H.E.S.S. detection. The source spectrum is well fit by a power-law function. Moreover, no significant flux variability is detected over the course of VERITAS observations. We place the VERITAS results in a multi-wavelength context to comment on the HESS J1943+213 classification.
Speaker: Karlen Shahinyan (University of Minnesota)
• 3:30 PM
VERITAS Observations of M31 (the Andromeda Galaxy) 1h
Diffuse gamma rays are tracers of cosmic rays, providing information on their origin and diffusion. M 31 (the Andromeda Galaxy) is the closest spiral galaxy to the Milky Way (d = 750 kpc) and is very well studied at all wavelengths, thus it is a prime target for the study of diffuse gamma-ray emission. The very-high-energy (VHE, E > 100 GeV) gamma-ray observatory VERITAS has conducted 45 hours of observations of M 31 and an upper limit on the VHE flux will be presented. An updated Fermi-LAT (100 MeV < E < 300 GeV) analysis will also be presented. These observations will be compared with predictions of the gamma-ray flux derived from the inelastic scattering of VHE cosmic rays of the interstellar medium (ISM) and the interstellar radiation field. M 31 provides an ideal opportunity to probe these mechanisms. Its proximity and spatial extent, significantly larger than the VERITAS point spread function but smaller than the field-of-view, enables the star-forming ring, 10 kpc from the galaxy core, with its dense ISM and numerous supernova remnants to be resolved.
Speaker: Ralph Bird (UCD Dublin)
• 3:30 PM
Water quality monitoring and measurement for the LHAASO-WCDA with the cosmic muon signals 1h
The Large High Altitude Air Shower Observatory (LHAASO) project is to be built at Daocheng, Sichuan Province, 4400 m a.s.l., in a few years. As one of the major components of the LHAASO project, LHAASO-WCDA, a water Cherenkov detector array with an area of 90000 m2, contains around 400,000 tons of purified water. To gain full knowledge of the water Cherenkov technique and to investigate the engineering issues, a 9-cell detector array has been built at the Yang-Ba-Jing site. With the array, a method of water quality monitoring and measurement with cosmic muon signals is studied, whose results show that a precision at some ten percentages can be achieved, satisfying the requirement of the experiment. The results are compared with those from a full Monte Carlo simulation. This method is proposed to be applied in the LHAASO-WCDA project.
Speakers: Dr Bo Gao (Institute of High Energy Physics, CAS), Prof. Chunxu Yu (School of Physics, Nankai University), Dr Hanrong Wu (Institute of High Energy Physics, CAS), Mr Huicai Li (School of Physics, Nankai University), Dr Mingjun Chen (Institute of High Energy Physics, CAS), Ms Xiaojie Wang (Institute of High Energy Physics, CAS), Prof. Zhiguo Yao (Institute of High Energy Physics, CAS)
• 3:30 PM 4:30 PM
Poster 1 SH Theater Foyer

Theater Foyer

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
• 3:30 PM
3D simulations of heliospheric propagation of heavy-ion solar energetic particles 1h
In recent years, a wealth of spacecraft measurements of heavy ion solar energetic particles have become available, thanks to data from the ACE and STEREO spacecraft. Interesting features in heavy ion time intensity profiles, such as the decay of the Fe/O ratio over time in some events, have been observed. Heliospheric propagation effects have been invoked in the literature as a possible cause of Fe/O decays. Recent modelling work has shown that drifts due to the gradient and curvature of the large scale Parker spiral magnetic field, are a significant source of perpendicular transport for partially ionised heavy ions. Modelling these effects requires a fully 3D description. Here we present results of 3D test particle simulations of heavy ion SEP propagation in the heliosphere, for a Parker spiral magnetic field in a variety of scattering conditions. We simulate intensity profiles of heavy ions as would be observed at 1 AU, and compare them with recent data from STEREO and ACE.
Speaker: Silvia Dalla (University of Central Lancashire)