Description
Poster Session & CERN Visit (50 People)
It is well known that CMB is a very powerful tool to constraints Dark Matter decays, even if this decay happens in some invisible -so called "dark"- radiation.
I would like to show that, in multi-component models, or more generally for non-trivial dark sector decoupled from standard model, CMB can constraints both lifetime and abundance of decaying dark matter into dark radiation (that could...
The firm establishment of gamma-ray sources of dark matter is often impeded by source confusion. Conventional astrophysical sources can mimic hypothetical dark matter sources, manifested in unidentified sources in the Fermi-LAT catalogues or in the GC excess. In statistical terms, the question of whether a sources is dark matter or conventional astrophsyics is an example of a non-standard ...
Our direct results on the IBL are consistent with those from complimentary \gray analyses using observations from the {\it Fermi}-LAT \gray space telescope and the H.E.S.S. air \v{C}erenkov telescope. Figure \ref{Ackermann} indicates how well our opacity results for $z = 1$ overlap with those obtained by the {\it Fermi} collaboration (Ackermann et al. 2012). Our results are also compatible...
The HAWC Observatory is able to perfom dark matter (DM) searches for annihilation or decay of TeV candidates. In the case of annihilation of DM particles, sub-structure enhancement in highly extended sources is important, and it is described through the astrophysical J factor. A related quantity is the boost factor, which quantifies how large the enhancement can be due to sub-structure effects...
The new generation of powerful instruments are reaching sensitivities and temporal resolutions that will allow a multi-messengers detection of transient phenomena. In this study, we explore the parameter-space of flaring sources (in particular in terms of luminosity, time-variability or emission energy band) that would enable the detection of transient neutrino signatures. We consider...
One of a promising asymmetric dark matter model is the mirror model, where the gauge group is doubled the standard model (SM) gauge group, i.e. SU(3)$_1$$\otimes$SU(3)$_2$ $\otimes$SU(2)$_L$$\otimes$SU(2)$_R$ $\otimes$U(1)$_{Y1}$$\otimes$U(1)$_{Y2}$, and the particles content consist of the ordinary (o) SM particles (plus the right handed neutrinos) and their parity mirror (m) partners. To...
In the framework of the Standard Model extended with a dark matter particle in curved spacetime, we investigate the impact of terms in the Lagrangian linear in the dark matter field and proportional to the Ricci scalar on the dark matter stability. We show that this non-minimal coupling induces decay even if the dark matter particle only has gravitational interactions, and that the decay...
A worldwide network of kilometer-scale laser interferometers will come into operation during the next several years. Future terrestrial and space-based detectors have also been planned. We investigate the use of gravitational-wave observatories as detectors of dark matter in the process of direct interaction of DM objects with detectors. We will present the prospects for a detection based on...
Cygnus X-1 is the prototype black hole high-mass microquasar.
As a persistent and bright X-ray source is considered an optimal candidate
to study the disk-jet coupling. It displays the typical soft and hard X-ray
spectral states of black hole binaries where the emission is dominated by
the thermal black body radiation and by non-thermal emission from the inner
part of the disk and the...
In this talk we introduce DRAGON2, the new version of the public
software package designed to study Cosmic Ray (CR) propagation in the Galaxy. Our
aim is to illustrate the approach followed in the writing of the code and to
present its most important features. We describe the properties of the numerical
scheme that has been adopted to implement all the processes related to CR
transport...
We consider a natural extension of the Minimal Dark Matter scenario where Dirac and Majorana SU(2)_L multiplets couple together via the Higss. We classify and study in a systematic way all the few possible models consistent with the absence of Landau poles up to very high scale, including the results for Direct Detection, and the Sommerfeld-enhanced annihilation. We demonstrate that, at...
Extensive air shower (EAS) arrays with muon identification capability are ideal
to investigate diffuse $\gamma$-rays at multi-TeV energies. The GRAPES-3
experiment at Ooty in India is equipped with a dense array of 400 scintillator
detectors and a large area (560 m$^2$) tracking compact muon detector. It is
designed to investigate $\gamma$-rays and cosmic ray nuclear composition in...
In this talk I will describe the main effects due to Einstein's general relativity on the stability of the electroweak vacuum. A perturbative (weak gravity) expansion will be discussed.
Local measurements of Galactic cosmic-ray antiprotons are known to provide constraints on the properties of annihilating cold dark matter (CDM). It is also known that CDM candidates generically lead to the structuring of matter on scales much smaller than typical galaxies. This clustering translates into a very large population of subhalos in galaxies, which induces an enhancement of the...
We estimate the annihilation (J) factors of non-spherical dark halos in the Galactic dwarf spheroidal (dSph) galaxies.
This is motivated by the fact that most of such estimations have so far treated the dSphs and their dark halos as spherical systems for simplicity, even though the luminous parts of dSphs as well as the shapes of dark halos predicted by cold dark matter simulations are not...
Weakly Interactive Massive Particles (WIMPs) are among the most favored Dark Matter candidates.
As the Solar System moves through Dark Matter halo, the WIMPs may scatter on the nuclei in the
Sun/Earth, lose energy, and get trapped by their gravitational potentials. Their capture and subsequent
annihilations in the core of Sun/ Earth may subsequently give rise to neutrinos, through various...
ANTARES is currently the largest neutrino telescope operating in the Northern Hemisphere, aiming at the detection of high-energy neutrinos from astrophysical sources. Such observations would provide important clues about the processes at work in those sources, and possibly help to understand the sources of very high-energy cosmic rays. In this context, Antares is developing several programs to...
The MAGIC telescopes can potentially detect very-high-energy gamma-rays emitted by multi-messenger sources.
One such interesting target that has been found recently, is astrophysical neutrino events.
Gamma-ray observations of neutrino directions have a potential to find hadronic gamma-ray emissions from the neutrino directions and to identify neutrino sources.
The IceCube Collaboration has...
Our galactic plane is a diffuse heterogeneous emitter at high and very high energies. Several gamma-ray campaigns, like that of Fermi-LAT in the GeV range and H.E.S.S. and Milagro in the TeV range, reported an enhanced diffuse emission from different regions of the plane. With a comprensive cosmic-ray transport model, able to reproduce the observed gamma-ray spectra from the galactic plane, we...
We perform a spectral and anisotropic one-point-fluctuation analysis of high-energy Icecube data, based on data-driven modelling of both galactic and extragalactic contributions to the flux.
In baseline scenarios, energetic astrophysical neutrinos are produced in decays of charged pions, which in turn originate from proton-proton or proton-gamma collisions. Neutral-pion decays produce an accompanying gamma-ray flux, and observational data on gamma rays and cosmic rays impose serious constraints on scenarios explaining the origin of IceCube high-energy events. I review these...
New observational tests of anomalies in absorption of gamma rays from distant sources, which may point to existence of light axion-like particles, are discussed. Constraints on parameters of the would-be axion-like particle are presented and various scenarios are tested.
Recently a potential correlation between the discovery of the IceCube PeV-neutrino event (IC 35) and the outburst phase of the blazar PKS B1424-418 has been reported. In this study, we simulate both the multi-wavelength photon and neutrino emission for this source using a self-consistent one-zone model. After a study on the parameter space we find that the simple hadronic model fails to...
Detection of ~ 0.1-70 GeV prompt gamma-ray emission from the exceptionally bright gamma-ray burst (GRB) 130427A by the Fermi-Large Area Telescope provides an opportunity to explore the physical processes of GeV gamma-ray emission from the GRB jets. In this work we discuss interactions of Iron and Oxygen nuclei with observed keV-MeV photons in the jet of GRB 130427A in order to explain an...
The current large area cosmic ray detector surface arrays typically measure only the net flux and arrival-time of the charged particles produced in an extensive air shower (EAS). Measurement of the individual charged particles at a surface array will provide additional distinguishing parameters to identify the primary and to map the very high energy interactions in the upper layers of the...
The main aim of the ANTARES neutrino telescope is to detect neutrinos from astrophysical sources. Due to its location, ANTARES has a privileged visibility of the Galactic Centre, which provides the most stringent sensitivities for this region for neutrino energies below 100 TeV. The latest results of the all-flavour neutrino analysis for point and extended sources using data from 2007 to 2015...
High-energy astrophysical neutrinos are a novel arena to test for the presence of new neutrino physics. With them, we can look for new physics at scales of tens of TeV to a few PeV, far beyond the reach of laboratory experiments. Even tiny modifications from new physics might accumulate over the presumed cosmological-scale baselines and become detectable. New physics models include, for...
Detecting ultra-high energy neutrinos (UHECNs) with energies above 10^17eV, or the GZK neutrinos, is a fundamental problem in neutrino astronomy. By finding GZK neutrinos, not only the GZK process can be verified, but also provides valuable insights of the ultra-high energy cosmic rays.
When UHECNs interact with ice, radio signals at the frequencies of few hundreds of MHz will be generated...
We use a two point correlation analysis to look for inhomogeneities in the arrival directions of the high energy muon neutrino candidates detected by the ANTARES neutrino telescope. This
approach is complementary to a point source likelihood-based search, which is mainly sensitive
to single point like sources and not to collective effects. We present the results of a search
based on this...
Abstract : Axion-like particles (ALPs) as an extension of the standard model define a generic class of light pseudo-sclars with a rich phenomenology because of their coupling to photons. Here we explore a so-far neglected opportunity to search for ALPs-photon coupling in the disappearance channel, i.e. a characteristic energy dependent suppression of gamma-rays. To verify this phenomenon...
We present the software StellarICs in development since 2013, year of the first release.
Dwarf spheroidals (dSphs) are low-luminosity satellite galaxies of the Milky Way highly dominated by dark matter. Therefore, they are prime targets to search for signals from dark matter annihilation using gamma-ray observations. Recent stellar kinematical data show that the dark matter density profiles are better described by axisymmetric profiles than by the traditionally used spherically...
One of the key predictions of the “WIMP” paradigm for Dark Matter (DM) is that DM particles can annihilate into charged particles. These annihilations will proceed in e.g. Galactic subhalos such as dwarf Galaxies or, as recently pointed out, high velocity clouds such as the “Smith” cloud. In this talk I will argue that among the several messengers of the DM annihilations occurring in the Smith...
Cen A is the nearest radio-galaxy detected as a VHE gamma-ray source. Discovered by the H.E.S.S. telescopes in Namibia, Cen A is a faint VHE gamma-ray emitter, and the flux derived from the H.E.S.S. data is much higher than that expected from a single zone SSC model which adequately describes the emission from Cen A at lower frequencies. New observations with H.E.S.S. were performed to...
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The presence of large scale TeVs anisotropy in Milagro, ARGO, ICECUBE
and today Hawc sky remain a mistery: how may charged cosmic rays at tens
TeV remain correlated while being bent by local solar and galactic
magnetic fields in an expected smeared nearly homogeneous maps? We
considered UHECR as mostly light (or partial heavy) radioactive nuclei
whose decay in flight may feed by alfa and...
S5 0716+714 is a well known BL-Lac object, characterized by an extreme variability across the whole electromagnetic spectrum. The discovery in the Very High Energy band (VHE, E> 100 GeV) by MAGIC happened in 2008, but at that time Fermi-LAT data were not yet available. During January 2015 the source went through the brightest optical state ever observed, triggering MAGIC follow-up...
The blazar S4 0954+65 (at a disputed redshift of z=0.368 or z>=0.45) underwent an exceptionally high state in optical during January and February 2015, as revealed by the Tuorla and St. Petersburg University blazar monitoring programs: a brightening of more than 3 magnitudes in the R-band from the average monitored states. Simultaneous data from the Fermi/LAT satellite at high energy gamma...
