2nd Anisotropic Universe Workshop: Unveiling the Anisotropic Universe

11 Apr 2016, 08:30 → 13 Apr 2016, 18:00 Europe/Zurich

Amsterdam

In this second edition of the Anisotropic Universe Workshop, “Unveiling the Anisotropic Universe”, we plan to have about 50 participants highly interested in debating the study of anisotropies in astrophysics and cosmology. We organized a similar workshop in September 2013 in Amsterdam (1st Anisotropic Universe Workshop) that was a success and resulted in several fruitful collaborations.

The study of anisotropies is a cross-field topic that is quickly developing thanks to the incredibly detailed data that we have been collecting during the last few years from microwaves, with Plank, up to very-high energies, with Fermi, just to cite two instruments. Our plan in to exploit the momentum that this cross-field topic is gaining to launch a collaborative effort to unravel fundamental issues in astrophysics and cosmology as, for example, the origin of ultra-high energy cosmic rays and neutrinos, and the nature of dark matter.

Monday, 11 April

08:30 → 09:00 Registration

09:00 → 09:10 Welcome/Introduction

09:10 → 10:30 Morning session (1)

Convener: Nicolao Fornengo (University of Torino and INFN/Torino)

09:10 Cosmological results from Planck 2015

Planck is an ESA satellite aimed at the observation of the Cosmic Microwave Background. In 2015, we released the second round of cosmological results based on full mission data both in temperature and, for the first time, in polarization. In this talk, I will review a few of the most interesting cosmological results of the 2015 year release. I will also present our current understanding of the agreement between the WMAP and Planck results.

Speaker: Silvia Galli

09:50 CMB phase shift and future bounds an axion couplings

Fluctuations in the cosmic neutrino background are known to produce a phase shift in the acoustic peaks of the cosmic microwave background. In this talk, I will revisit the phase shift of the CMB anisotropy spectrum as a probe of new physics, especially light and weakly-coupled species. The phase shift is particularly interesting because its physical origin is strongly constrained by the analytic properties of the Green's function of the gravitational potential. Then, I will provide observational constraints from the Planck temperature and polarization data on additional forms of radiation and comment on forecasts of the capabilities of future CMB Stage IV experiments. This then sets the stage for the discussion of constraints on the coupling of light thermal relics, in particular scalar particles, to the Standard Model. I will present new bounds on these weak couplings which have the potential to improve on current constraints by several orders of magnitude with measurements of future CMB experiments alone.

Speaker: Benjamin Wallisch (University of Cambridge)

BenjaminWallisch.pdf

10:10 Anisotropies and Inhomogeneities on the Largest Cosmic Scales

In this talk, I shall review innovative techniques that will allow next-generation experiments to tackle some of the most fundamental questions of contemporary cosmology: the nature of gravity, inflation and dark energy. Oncoming experiments such as the ESA Euclid satellite or the Square Kilometre Array will, for the first time, open a window onto the largest cosmic scales. Such scales, near or above the horizon, are uncontaminated by the non-linear growth of structure and by baryonic/astrophysics feedback. They can teach us about inflation and the physics of the early Universe. By studying anisotropies and inhomogeneities in the density perturbations on such extremely large scales we could measure relativistic effects that only become detectable on the scale of the horizon. Thus, we could further confirm - or disprove - Einstein's gravity on cosmological distances. Similarly, primordial non-Gaussianity and modified gravity can hide their effects near and above the cosmological horizon. Their signatures on ultra-large scales will improve our knowledge on inflation and the rôle of dark energy or modified gravity in the late-time accelerated expansion of the Universe.

Speaker: Dr Camera Stefano (Jodrell Bank Centre for Astrophysics)

StefanoCamera_2ndAnisotropicUniverse.pdf

10:30 → 11:00 Coffee break

11:00 → 12:30 Morning session (2)

Convener: Nicolao Fornengo (University of Torino and INFN/Torino)

11:00 Near-field Cosmology

Our Local Universe may well be the best-observed volume of the Universe, but it is also a disruptive factor when it comes to observe beyond it. Using positions and peculiar velocities of more than 8,000 galaxies from the second Cosmicflows catalog, we are now able to reproduce in Constrained Local UniversE Simulations the full three dimensional distribution of matter in the observed nearby large-scale structure with an accuracy of a few megaparsecs. The nearby objects like Virgo, the Local Group, etc, can be studied in great details and compared directly with observations. Therefore, in future high precision observational surveys, the foreground effect of the Local Universe can be accounted for.

Speaker: Jenny Sorce

amsterdam_jenny_sorce_withoutadditionalslides.pdf

11:40 The infrastructure of voids: on void hierarchy, void galaxies and the Local Void

I will review the hierarchical evolution of voids, discussing how they build up the void population via the processes of merging and collapse. On the basis of the Multiscale Watershed Void Finder we investigate the systematics of void evolution in adhesion models of structure formation. Subsequently, we follow the evolution of walls, filaments and haloes in the interior of void regions in the high-resolution LCDM CosmoGrid simulation. The results will be connected to the filamentary void galaxy configuration VGS31 in SDSS. Finally, we turn towards the structure of the Local Void, and follow its dynamical evolution on the basis of an adhesion-based reconstruction of the Cosmic Web in the local Universe.

Speaker: Rien van de Weijgaert (U)

voids.infrastructure.grappa_2ndanisotr.apr2016.pdf

voids.infrastructure.grappa_2ndanisotr.apr2016.pptx

12:10 News from the Dark Energy Survey

The Dark Energy Survey (DES) is a galaxy photometric survey designed to study the properties of the Dark Energy using four main cosmological probes: galaxy clustering on large scales, weak gravitational lensing, galaxy-cluster abundance, and supernova distances. During the northern fall of 2012 the DES collaboration installed and commissioned DECam, a 570 mega-pixel optical and near-infrared camera with a large 3 sq. deg. field of view, set at the prime focus of the Víctor M. Blanco 4-meter telescope in CTIO, Chile. A \"Science Verification\" (SV) period of observations, lasting until late February 2013, followed the DECam commissioning phase, and provided science-quality images for almost 200 sq. deg. at the nominal depth of the survey. The survey is now finishing its third year of observation. At the end of the five seasons, DES will have mapped an entire octant of the southern sky to unprecedented depth, measuring the position on the sky, redshift and shape of almost 300 million galaxies, together with thousands of galaxy clusters and supernovae. In this talk, I will present the current status of the project and the first scientific results of the survey, based on the Science Verification data, with a focus on the cross-correlations between the DES data and the CMB observations by Planck and SPT.

Speaker: Dr Aurélien Benoit-Lévy (Institut d'Astrophysique de Paris)

ABL_DES_Amsterdam.pdf

12:30 → 14:00 Lunch break

14:00 → 15:20 Afternoon session (1)

Convener: Mattia Fornasa (GRAPPA Institute (University of Amsterdam))

14:00 Cosmological anisotropies and neutrino properties

Speaker: Julien Lesgourgues

16.04.21_Amsterdam_Lesgourgues.pdf

14:20 The halo model in the era of precision Cosmology and accurate Astrophysics

The halo model has become a standard framework to interpret the clustering statistics and the weak lensing signal of dark matter dominated structures, like galaxies or clusters of galaxies. I will review the halo model formalism and discuss how on-going optical wide area surveys like KiDS, DES, HSC and complete spectroscopic surveys like GAMA allow to test in great details some of the main assumptions of the model. I will also discuss how the halo model framework can be extended to account for the fact that the galaxy-halo connection might not only be governed by the halo mass but also by the formation time of halos and how it can be optimised to reproduce the matter power spectrum in highly non-linear regimes, eventually including also effects coming from baryon feedback at small scales.

Speaker: Massimo Viola

15:00 Correlations in the radio background

Recent estimates of the extragalactic radio background revealed the probable presence of a population of faint but numerous sources contributing for the majority of the background emission. In this talk, I will discuss how to test this hypothesis by studying 1-point and 2-point correlations in the radio sky. I will outline relevant current data and analysis, and highlight forecasts for the SKA and its precursors.

Speaker: Marco Regis (INFN - National Institute for Nuclear Physics)

AnisotropicGRAPPA_Regis.pdf

15:20 → 15:40 Coffee break

15:40 → 17:00 Afternoon session (2)

Convener: Mattia Fornasa (GRAPPA Institute (University of Amsterdam))

15:40 Fluctuations in the Near Infrared (and X-ray) Background

Speaker: Dr Ruben Salvaterra (IASF)

Amsterdam2016_Salvaterra.pdf

16:20 Anisotropies of the cosmic X-ray background: Challenging results from angular correlation studies with XBOOTES

Angular correlation studies of the cosmic X-ray background (CXB) fluctuations are becoming a new frontier of performing large-scale structure (LSS) studies with X-ray surveys, thanks to the accurate knowledge of X-ray luminosity functions, growing X-ray survey areas, and the high angular resolution of the current and future generations of X-ray telescopes. These studies give us access to faint and low luminosity X-ray source populations, which are hardly accessible be current and future LSS studies with resolved source samples. I demonstrate with the Chandra survey XBOOTES (~9deg^2) that we can put new constraints on clustering properties on Active Galactic Nuclei (AGN) and galaxy clusters via CXB fluctuation studies with current and future large X-ray surveys. Thanks to the large area of XBOOTES, we have conducted the most accurate measurement to date of the angular correlations of the CXB fluctuations (0.5-2.0keV) for angular scales of <~17'. I will show that the CXB fluctuations above angular scales of ~2' originate dominantly from galaxy clusters, while below 2' they originate dominantly from unresolved AGN. We are the first to measure this transition zone and the clustering signal of galaxy clusters at small angular scales (~2' - 17'), where high-redshift (z>0.5) galaxy clusters are important. Further, we can show that at our given precision the clustering signal of the unresolved AGN population (median luminosity Lx ~ 10^{42.6}) is consistent with the assumption that a dark matter halo only hosts one AGN. This agrees with our current understanding of AGN triggering/fueling mechanisms.

Speaker: Dr Alexander Kolodzig (KIAA (Kavli Institute for Astronomy and Astrophysics at Peking University))

Talk_XBOOTES_CXB_LSS_15min.pdf

16:40 Probing isotropy of cosmic acceleration by Type Ia supernovae

We present a method to test the isotropy of the magnitude-redshift relation of Type Ia Supernovae (SNe Ia) and single out the most discrepant direction (in terms of the signal-to-noise ratio) with respect to the all-sky data. Our technique accounts for possible directional variations of the corrections for SNe Ia and yields all-sky maps of the best-fit cosmological parameters with arbitrary angular resolution. To show its potential, we apply our method to the recent Union2.1 compilation, building maps with three different angular resolutions. We use a Monte Carlo method to estimate the statistical significance with which we could reject the null hypothesis that the magnitude-redshift relation is isotropic based on the properties of the observed most discrepant directions. We find that, based on pure signal-to-noise arguments, the null hypothesis cannot be rejected at any meaningful confidence level. However, if we also consider that the strongest deviations in the Union2.1 sample closely align with the dipole temperature anisotropy of the cosmic microwave background, we find that the null hypothesis should be rejected at the 95−99 per cent confidence level, slightly depending on the angular resolution of the study. If this result is not due to a statistical fluke, it might either indicate that the SN data have not been cleaned from all possible systematics or even point towards new physics. We finally discuss future perspectives in the field for achieving larger and more uniform data sets that will vastly improve the quality of the results and optimally exploit our method.

Speaker: Mr Behnam Javanmardi (Argelander Institute for Astronomy)

javanmardi_SN_isotropy.pdf

17:00 → 18:00 Open discussion

Speaker: Dr Aurelien Benoit-Levy

Tuesday, 12 April

09:00 → 10:20 Morning session (1)

Convener: Miguel Sánchez-Conde (Oskar Klein Centre, Stockholm University)

09:00 Fermi-LAT measurement and origin of the Extragalactic Gamma-Ray Background

Speaker: Gabrijela Zaharijas (CEA Saclay)

Zaharijas_CosmoWIMP_Amsterdam_v0.pdf

09:40 Looking to Dark Matter through gamma-ray anisotropies

Anisotropies in the extragalactic electromagnetic emission originated from dark matter represent an emerging tool in the quest for a particle dark matter signal. These anisotropies are due to the cumulative emission from unresolved dark matter structures, which are present at any scale: galaxy clusters, individual galaxies, subhalos inside galaxies. The same structures can be probed by gravitational tracers of the dark matter distribution in the Universe: this is obtained by large-scale-structure surveys, but in the future a good wealth of additional and complementary information will be available from weak lensing surveys. The study of gamma-rays anisotropies and the cross-correlation between the dark matter signal and gravitational tracers offer a novel and potentially very powerful opportunity to probe the particle physics nature of dark matter. The talk will introduce details and features of gamma-rays anisotropies and give perspectives of the cross-correlation approach.

Speaker: Nicolao Fornengo (University of Torino and INFN/Torino)

fornengo.pdf

10:20 → 10:35 Coffee break

10:35 → 12:35 Morning session (2)

Convener: Miguel Sánchez-Conde (Oskar Klein Centre, Stockholm University)

10:35 Dissecting the high-latitude gamma-ray sky with photon-count statistics

In the recent past, statistical image analysis techniques have been proven to provide unprecedented sensitivity for decomposing gamma-ray sky maps. In this talk, I will use statistical properties (the 1-point PDF) of the Fermi-LAT photon counts map to measure the composition of the gamma-ray sky at high latitudes. I will introduce a new method, generalizing the use of standard pixel-count statistics, and summarize first results on the decomposition of the observed gamma-ray emission into (a) point-source contributions, (b) the Galactic foreground contribution, and (c) a truly diffuse isotropic background contribution. Our new measurements improve beyond catalog detection limits by about one order of magnitude. The talk will conclude with an overview of implications and future prospects.

Speaker: Dr Hannes Zechlin (University of Torino)

1pPDF_dNdS_grappa_zechlin_web.pdf

10:55 High-energy Astrophysics in a single pixel

The one-point function (i.e., the isotropic flux distribution) is a complementary method to (anisotropic) two-point correlations. Using analytical models of structure formation and dark matter halo properties, we compute the gamma-ray flux distribution due to annihilations in extragalactic dark matter halos, and relate this to indirect DM searches with Fermi Large Area Telescope. Using luminosity functions of star forming galaxies, BL Lacs, and other high-energy neutrino sources, we compute the flux distribution to be compared with the flux observed by IceCube.

Speaker: Michael Feyereisen (University of Amsterdam)

Feyereisen.pdf

11:15 Updated measurement of gamma-ray anisotropies

Speaker: Mattia Fornasa (GRAPPA Institute (University of Amsterdam))

AnisotropicUniverse.pdf

11:35 Tomography of the Fermi-LAT diffuse extragalactic signal via cross-correlation with galaxy catalogues

Speaker: Alessandro Cuoco (U)

Cuoco_AMS_2ndAnisotropicUniverse_April2016.pdf

12:15 Anisotropic Universe unveiled with new galaxy catalogs

Various cosmological studies require wide-angle galaxy catalogs with 3-dimensional information on source positions. Such datasets, when covering a significant fraction of the sky, are particularly useful for cross-correlation techniques allowing to detect signals buried under the noise in auto-correlations. I will present two recently compiled photometric redshift catalogs covering most of the extragalactic sky, which give access to unprecedented angular scales up to redshifts of z~0.4. The two datasets are: 2MASS Photometric Redshift catalog (2MPZ) of 1 million galaxies on 90% of the sky at a median redshift z=0.07, and WISE x SuperCOSMOS catalog of 20 million galaxies on 70% of the sky at a median redshift z=0.2. Their redshift accuracy (respectively dz=0.013 and dz=0.033) is sufficient for the tomographic approach in cosmological correlations, and the large fraction of sky covered enhances the signal-to-noise of such studies. I will discuss some of the applications of the two datasets, including a cross-correlation with the Fermi gamma-ray background for constraints on dark matter annihilation and decay (in collaboration with A Cuoco). Finally I will present possibilities of reaching for greater depths on large angular scales thanks to combining already available and forthcoming datasets such as from WISE, VHS, KiDS, etc.

Speaker: Maciej Bilicki (Leiden University)

MBilicki.AnisotrUniv.04.2016.pdf

12:35 → 14:00 Lunch break

14:00 → 15:20 Afternoon session (1)

Convener: Shin'ichiro Ando (University of Amsterdam)

14:00 Spatial signature of Dark Matter in the Galaxy

A generic prediction of simulations of structures formation is the presence in our Galaxy of a population of dark matter subhaloes, hosted by the main dark matter halo. The annihilation of dark matter particles in those objects may lead to the production of gamma rays, inducing small scale fluctuations in the gamma-ray diffuse emission. In order to understand the origin and the composition of the anisotropy signal measured by the Fermi-LAT, it is crucial to estimate what can be the contribution from the dark matter distribution in the Galaxy. I will present predictions for the gamma-ray anisotropy from dark matter annihilation based on the most recent hydrodynamic simulations of galaxy formation. I will discuss if and how baryons affect the predicted anisotropy signal and what are the main uncertainties at stake. Finally, I will show what are other possible signatures of dark matter subhaloes and what is the sensitivity of current telescopes.

Speaker: Francesca Calore (University of Amsterdam)

Calore_Anisotropy.pdf

14:20 Correlated statistical noise in power spectrum measurements

Observations of cosmic gamma-ray or neutrino events is a Poisson point process on the sphere with 2D spatial correlations sourced by the skymap of astronomical sources. With this perspective, the statistical distribution of the power spectrum of observed events can be expressed exactly, depending only on the number of events N and the angular flux distribution of sources. This talk explores the consequences of correlated statistical noise between the power spectrum at different multipoles. The particular case study considered is the search for a spectral line in a white diffuse background, using the mean-weighted power spectrum C. Anisotropy techniques are especially suited for detecting radiation from dim sources that are highly clustered. The statistical uncertainty of C has a term due to the correlated noise that dominates in the limit of low N. This has only a small effect on experiments with an instrument response like Fermi-LAT and event flux above 1 GeV. However, this term prevents improved instrument angular resolution from taming the noise in measurements of C. Thus, improved measurements of C for the diffuse gamma-ray background above 1 GeV requires larger effective areas. This fact, coupled with the fact that the statistical error of C decreases rapidly as 1/N, provides strong motivation for extending the lifetime of the Fermi satellite program.

Speaker: Sheldon Campbell (The Ohio State University)

Anisotropic_Universe_Campbell.pdf

15:00 Probing WIMP Dark Matter with gamma rays and over 1000 deg^2 of weak lensing data

Weakly interacting massive particle (WIMP) dark matter has a small but non-zero interaction cross-section with standard model physics. Gamma-rays from dark matter annihilations could then be observable by gamma-ray telescopes such as Fermi-LAT and used to constrain the annihilation cross-section. Cross-correlation of gamma-rays with tracers of dark matter improves the sensitivity and avoids many of the systematics inherent to auto-correlation analyses. Gravitational lensing is an unbiased tracer of matter and thus a prime candidate to cross-correlate the gamma-ray sky with. I will present the cross-correlation of Fermi-LAT gamma-rays with CFHTLenS, RCSLenS, and KiDS weak lensing data-sets, covering a total area of over 1000 deg2, and the resulting constraints on the WIMP annihilation cross-section.

Speaker: Tilman Troester (University of British Columbia)

TilmanTroester.pdf

15:20 → 15:40 Coffee break

15:40 → 16:20 Afternoon session (2)

Convener: Shin'ichiro Ando (University of Amsterdam)

15:40 Characterization of subhalo structure properties and implications for Dark Matter annihilation signals

A prediction of the standard LCDM cosmological model, also confirmed by N-body cosmological simulations, is that dark matter (DM) halos are teeming with numerous self-bound substructure, or subhalos. The precise properties of these subhalos represent important probes of the underlying cosmological model. Subhalos may also play a key role on the search for DM via its annihilation products. In particular, previous work has shown that subhalos are expected to boost the DM signal of their host halos significantly (so-called subhalo boost). Yet, these works have traditionally assumed that subhalos exhibit similar structural properties than those of main halos of the same mass, while it is well known from simulations that subhalos are more concentrated. In this work, we refine the substructure boost model of Sanchez-Conde & Prada (2014) by taking into account this and other effects. We use N-body simulation data from the Via Lactea II and ELVIS Milky Way-size simulations to learn about the structure of subhalos with masses 1e6 - 1e11 Msun/h. We do so in a way which is independent of any assumption on the DM density profile. Building upon this knowledge, we then provide a set of fits that accurately describe the subhalo structure, and use them to compute the boost. The new values are a factor 2-3 higher than the previous ones. We further refine our boost model to include unavoidable tidal stripping effects on the subhalo population. For main halos, this only introduces a moderate (20-30%) suppression of the boost values. Yet, for subhalos like those hosting the dwarf satellite galaxies of the Milky Way, tidal stripping does play a critical role, the total boost for these objects being only at the level of a few tens of percent in the most optimistic cases. Finally, we provide a parametrization of the boost factor for main halos that can be safely applied over a wide halo mass range.

Speaker: Miguel Sánchez-Conde (Oskar Klein Centre, Stockholm University)

GRAPPA_subbosts_masc_120416.pdf

16:00 Looking for unresolved point-like sources: the wavelet ways

A clear excess in the Fermi-LAT data is present at energies around a few GeV. The spectrum of this so-called 'GeV excess' is remarkably similar to the expected annihilation signal of WIMP dark matter. However, a large bulge population of sub-detection-threshold millisecond pulsars (MSPs) could also explain the excess spectrum. In a recent work we optimized the search for sub-threshold sources by applying a wavelet transform to the Fermi gamma-ray data. In the Inner-Galaxy the wavelet signal is significantly enhanced, providing supportive evidence for the point source interpretation of the excess. In this talk I will discuss the identification of point sources using a wavelet analysis. In addition, I will compare the performance of the wavelet to other techniques that can be used to identify anisotropies due to point sources, such as the autocorrelation function.

Speaker: Richard Bartels (University of Amsterdam)

BARTELS_ANISTROPIC_UNIVERSE2_2016.pdf

16:20 → 17:20 Open discussion

Speaker: Jennifer Gaskins

2016-04-12_AnisoUniverse_Discussion.pdf

19:00 → 21:00 Social Dinner

Wednesday, 13 April

09:00 → 10:20 Morning session (1)

Convener: Jacco Vink (University of Amsterdam)

09:00 Anisotropy and subtle aspects of cosmic-ray transport

Speaker: Pasquale Blasi

BlasiApril13-2016.key

09:40 Cosmic-ray anisotropies above the ankle

The distribution of the arrival directions of Ultra High Energy Cosmic Rays has shown to be remarkably isotropic. However, some indications of large and intermediate scale anisotropies have recently been reported by the Pierre Auger and Telescope Array observatories. I will review the results of these observations and discuss possible interpretations.

Speaker: Silvia Mollerach (CONICET)

mollerach.pdf

10:20 → 10:40 Coffee break

10:40 → 12:40 Morning session (2)

Convener: Jacco Vink (University of Amsterdam)

10:40 Probing anisotropies in arrival directions of astrophysical neutrinos

The origin of the flux of TeV-PeV neutrinos observed with IceCube is still a mystery. Various scenarios have been considered, ranging from conventional Galactic or extragalactic sources to exotic production mechanisms like PeV dark matter decay. One possibility to distinguish these models is via their distinctive anisotropy patterns in the arrival direction of neutrinos. So far, the data do not show strong signs of anisotropy, consistent with a diffuse neutrino background. However, this signal might be just hidden by the limited event statistics and angular resolution. I will review the status of anisotropy studies of IceCube data and the resulting limits on neutrino emission scenarios.

Speaker: Markus Ahlers

Ahlers_Anisotropy_Workshop_2016.pdf

11:20 Neutrinos and gamma rays as messengers of extragalactic astrophysical sources

The discovery of PeV neutrinos by the IceCube neutrino telescope opened the high-energy neutrino astronomy era. I will discuss multi-messengers techniques to pinpoint the eventual origin of the IceCube events and constrain the physics of cosmic accelerators.

Speaker: Irene Tamborra

Anysotropic_irene.pdf

12:00 Do high-energy astrophysical neutrinos trace star formation?

The IceCube Neutrino Observatory has provided the first map of the high energy (∼ 0.01 – 1 PeV) sky in neutrinos. Since neutrinos propagate undeflected, their arrival direction is an important identifier for sources of high energy particle acceleration. We present a statistical analysis of positional coincidences of the IceCube neutrinos with known astrophysical objects from several catalogs. When considering starburst galaxies with the highest flux in gamma-rays and infrared radiation, up to n = 8 coincidences are found, representing an excess over the ∼4 predicted for the randomized, or “null” distribution. The probability that this excess is realized in the null case, the p-value, is p = 0.042. This value falls to p = 0.003 for a partial subset of gamma-ray-detected starburst galaxies and superbubble regions in the galactic neighborhood. Therefore, it is possible that starburst galaxies, and the typically hundreds of superbubble regions within them, might account for a portion of IceCube neutrinos.

Speaker: Kimberly Emig (Leiden Observatory)

Emig_160413amsterdam.pdf

12:20 Using event pairs to search for point-like sources in high-energy neutrino data

he origin of astrophysical neutrinos remains a mystery. The first detections of TeV-PeV neutrinos by the IceCube Observatory found their arrival directions showing no departure from isotropy, implying that to detect point sources, both order-of-magnitude more statistics and more advanced search tools are needed. In this talk we discuss a maximum-likelihood method for search of point-like sources utilizing event pairs. We show that when a decent angular resolution is available, this method is capable of reducing the false positive and negative errors by about 50% comparing to the traditional search method using individual events. We conclude with implications of our method to future neutrino data and experiments.

Speaker: Ke Fang (University of Maryland)

Fang_2ndAnisotropicUniverse.pdf

12:40 → 14:10 Lunch break

14:10 → 15:10 Afternoon session

Convener: Kumiko Kotera (Institut d'Astrophysique de Paris)

14:10 The Astrophysical Multimessenger Observatory Network

The most energetic astrophysical phenomena, produce a range of “messengers” from photons and neutrinos, to cosmic rays and gravitational radiation. These messengers carry details of the energetics and physical conditions in these sources. The Astrophysical Multimessenger Observatory Network (AMON) aims to discover new particle astrophysics phenomena by merging the world's leading multimessenger observatories into a single data system for the first time. The facilities linked by AMON observe high-energy neutrinos (the IceCube and ANTARES Neutrino Observatories), the strongly-interacting nuclei observed as cosmic rays (the Pierre Auger Cosmic Ray Observatory), and in future phases, gravitational waves (the Advanced LIGO and VIRGO gravitational-wave detectors). AMON has been receiving and distributing IceCube neutrino alerts to partner observatories in real-time as of mid-2015. In this talk I will give an overview of the current status and near-future plans of AMON, focusing on the contribution of IceCube and the Pierre Auger Observatory.

Speaker: Foteini Oikonomou (Penn State University)

Oikonomou_13_4_16.pdf

14:30 Observations of gravitational waves from a binary black hole merger GW150914 and their implications

Speaker: Dr Nissanke Samaya (Radboud University)

15:20 → 15:40 Coffee break

15:40 → 16:40 Open discussion

Speaker: Pasquale Blasi (INAF)