| Speaker | Title | Abstract |
| Claudia Nones | Direct search for Dark Matter with the EDELWEISS-II experiment: status and results | The EDELWEISS-II experiment, located in the Laboratoire Souterrain de Modane,
is dedicated to the direct detection of dark matter particles with bolometric detectors.
In its current configuration it consists of an array of ten 400 g heat-and-ionization cryogenic detectors equipped
with interleaved electrodes for the rejection of near-surface events.
Results coming from six months of continuous operation will be presented. The observation of one nuclear recoil
candidate above 20 keV in an effective exposure of 144 kg.d is interpreted in terms of limits on the cross-section of
spin-independent interactions of WIMPs and nucleons. A cross-section of 10^-7 pb
is excluded at 90%CL for a WIMP mass of 80 GeV/c2. This result demonstrates for the first time the very high background
rejection capabilities of these simple and robust detectors in an actual WIMP
search experiment.
The continuation of the present run should result in Spring 2010 in a doubling of the present sensitivity.
By summer 2010, new detectors will be installed, which might allow to identify unambiguously a possible signal,
or pursue a deeper exploration of even more elusive WIMPs. |
| Alfredo Davide Ferella | Dark Matter direct search with the XENON100 experiment. Results and perspectives. | The aim of the XENON100 experiment is to directly detect cold dark matter particles via their elastic collisions
with Xenon nuclei. On this purpose a ultra-low background double phase (liquid-gas)
xenon filled time projection chamber with a total mass of 161 kg (62 in the target region and
99 kg in the active shield) has been installed at the Gran Sasso Underground Laboratory and is currently taking
science data. In this talk the design and performance of the detector and its associated systems will be presented.
Moreover the most recent data analysis will be presented along with the results. |
| Miguel Pato | Systematic uncertainties in the determination of the local dark matter density | We quantify systematic uncertainties associated with the determination of the local dark matter density from dynamical measurements in our Galaxy. Using very recent high-resolution N-body simulations of Milky Way like galaxies with and without baryons, we study the effect of baryonic physics on dark matter halos and how this can bias the inference of the dark matter density in our neighbourhood. Such piece of information is crucial in interpreting the results from direct detection dark matter experiments |
| Riccardo Catena | A novel determination of the local dark matter density |
We present a novel study on the problem of constructing mass models for the Milky Way, concentrating on features
regarding the dark matter halo component. We have considered
a variegated sample of dynamical observables for the Galaxy, including several results which have
appeared recently, and studied a 7- or 8-dimensional parameter space - defining the Galaxy model - by implementing a
Bayesian approach to the parameter estimation based on a Markov Chain Monte Carlo method. The main result of this analysis
is a novel determination of the local
dark matter halo density which, assuming spherical symmetry and either an Einasto or an NFW density profile is found to be
around 0.39 GeV cm^-3 with a 1-sigma error bar
of about 7%. This is in contrast to the standard assumption that the local dark matter density
is about 0.3 GeV cm^-3 with an uncertainty of a factor of 2 to 3. A very precise determination of the local halo
density is very important for interpreting direct dark matter detection experiments. Indeed the results we produced,
together with the recent accurate determination of the local circular velocity, should be very useful to considerably
narrow astrophysical uncertainties on direct dark matter detection. |
| Paolo Salucci (SISSA) | The distribution of dark matter in galaxies | In the past years a wealth of observations has unraveled the structural properties of the Dark matter distibutions distribution in galaxies, expecially in spirals. These have pointed out to an intriguing scenario not easily explained by present theories of galaxy formation. The investigation of individual and coadded kinematics has shown that the spiral rotation curves follow, from their centers out to their virial radii, a Universal profile (URC) that arises from the tuned combination of a stellar disk and of a dark halo. The importance of the latter component decreases with galaxy mass. Individual objects, on the other hand, have clearly revealed that the dark halos encompassing the luminous discs have a constant density core. This resulting observational scenario may pose important challenges to presently favored theoretical LambdaCDM Cosmology. |
| Speaker | Title | Abstract |
| Keith Rielage | The MiniCLEAN dark matter experiment | The MiniCLEAN experiment utilizes over 500 kg of liquid cryogen to detect nuclear recoils from WIMP dark matter
with a projected sensitivity of 2x10^-45 cm2 for a mass of 100 GeV. The liquid cryogen is interchangeable between argon
and neon to study the A^2 dependence of the potential signal and examine backgrounds. MiniCLEAN utilizes a unique modular
design with spherical geometry to maximize the light yield using cold photomultiplier tubes in a single-phase detector.
Pulse shape discrimination techniques are used to separate nuclear recoil signals from electron recoil backgrounds.
Particular attention is being paid to mitigating the backgrounds from contamination of surfaces by radon daughters during
assembly. The design and assembly status of the experiment will be discussed. The projected timeline for staging the experiment
at SNOLAB in Sudbury, Canada will be presented. |
| Kazuyoshi Kobayashi | XMASS experiment | XMASS experiment is now aiming to detect WIMP directly using 800kg Liquid Xenon target. We are going to finish
the detector construction this summer and start data taking. We present the status of the XMASS experiment. |
| Ursina Degunda | The ArDM Experiment, a Double Phase Argon Calorimeter and TPC for Direct Detection of Dark Matter | The aim of the ArDM (Argon Dark Matter) experiment is the direct detection of WIMPs (weakly interacting massive particles),
candidates for Dark Matter, using a one ton double phase argon calorimeter and TPC. The detection is based on the independent
read out of the ionisation electrons and scintillation light caused by elastic scattering of the WIMPs on the argon nuclei in
the liquid phase.
In this talk the detector design as well as scintillation light measurements with cosmic muons and external radioactive
sources will be presented. Furthermore, results of a first run with an applied electric drift field of about 1 kV/cm will be shown,
including the liquid argon purity, the electron drift velocity and the uniformity of the drift field. |
| Juan Estrada | Low threshold DM search with CCDs | We present a direct search for dark matter particles using fully-depleted high-resistivity CCD detectors. These detectors have a very low electronic readout noise (RMS~7 eV), allowing a low detection threshold. The results of the first 2009 engineering are discussed, together with the results from the on going 2010 run. The plans for future developments are also presented. |
| Qian YUE | The recent status of CJPL and CDEX |
China JinPing Deep Underground Laboratory (CJPL) which has more than 2500 m of rock overburden is under construction and
will be run in September, 2010. It can be accessed through a road tunnel of length 17.5 km, and is supported by services
and amenities near the entrance provided by the local Hydropower Plant. The recent status and schedules of the construction
of CJPL will be reported. The first dark matter experiment who will be run from September 2010 in CJPL is CDEX (China Darkmatter
EXperiment) which deploy an Ultra-Low-Energy Germanium detector based on Point-Contact Technology for WIMP dark matter searches,
especially at the 1-10 GeV mass range. The conceptual design of the experiment will be discussed. Future plans and prospects of
the laboratory will also be surveyed. |
| Speaker | Title | Abstract |
| Wystan Benbow | Results form VERITAS Extragalactic Observations | Over the past eight years remarkable progress has been made in Very High Energy (VHE; E > 100 GeV) gamma-ray astrophysics. The VHE source catalog has increased from only ~10 sources to ~100 sources belonging to a wide variety of source classes, and includes ~30 extragalactic objects. The Very Energetic Radiation Imaging Telescope Array System (VERITAS) is currently the world's most sensitive detector of astrophysical VHE gamma rays. It has observed more than 100 extragalactic objects, primarily blazars. Highlights from the VERITAS extragalactic observation program will be presented. |
| Paolo Maestro | Cosmic ray energy spectra up to 10^14 eV from the 1st CREAM flights | |
| Patrick Berghaus | Cosmic Ray Physics with IceCube | IceCube is composed of the surface array IceTop and the volume detector InIce/DeepCore. This offers unique opportunities for cosmic-ray physics. One major objective is the measurement of cosmic-ray composition around and above the knee by correlating the electromagnetic content of air showers to the high-energy muon yield. Presented is the status of the surface air shower array and first results from analyses using cosmic-ray muons in the in-ice detector. These include a measurement of the correlation between muon flux and stratospheric temperature. Prospects for a measurement of the atmospheric muon spectrum will be discussed. |
| Segev BenZvi | Observation of Structure in the Arrival Directions of Cosmic Rays at TeV with IceCube | The IceCube Neutrino Observatory, located at the South Pole, comprises several thousand optical modules buried in the Antarctic ice sheet at depths between 1400 and 2400 meters. While the IceCube detector is designed to observe the sources of extragalactic neutrinos, it is also sensitive to the deeply-penetrating downgoing muons produced by cosmic ray air showers at 1 TeV. Since the start of data taking in 2007, the detector has recorded tens of billions of muon events, and has accumulated the largest sample of TeV cosmic ray measurements ever recorded in the southern hemisphere. Using the high-statistics muon data measured with IceCube, we have observed departures from isotropy at the per mille level in the arrival direction distribution of the cosmic rays. The observations appear to be a continuation of structures observed in the northern sky by several experiments; however, their ultimate origin remains unknown. We will discuss the observations of cosmic ray anisotropy performed with the IceCube detector, our procedures for validating these observations, and plausible source scenarios for the structures observed in the TeV cosmic ray data. |
| Speaker | Title | Abstract |
| Yves Gallant for the CTA consortium | TeV Galactic Source Physics with CTA | We demonstrate how CTA, the planned next-generation array of imaging atmospheric Cherenkov telescopes (IACTs), will address many currently unresolved issues on the physics of Galactic TeV gamma-ray sources. The current generation of IACT instruments has given us our first view of the richness of the Galaxy in TeV sources. The majority of these are associated with end products of massive star evolution, including several supernova remnants (SNRs) and many pulsar wind nebulae (PWNe). SNRs are the most plausible sources for hadronic Galactic cosmic rays, while PWNe are likely sources of high-energy cosmic-ray electrons and positrons; their detection in TeV gamma-rays provides direct evidence for the acceleration of charged particles up to several tens of TeV in these objects. We outline currently unresolved issues in these sources, and discuss the progress expected from the capabilities of CTA. Its major improvement in sensitivity will allow the detection of a much larger population of these objects; in particular, representative SNRs will be detectable throughout the Galaxy, and representative PWNe out to the distance of the Magellanic Clouds. |
| Rosa Coniglione | KM3NeT: a project for an underwater cubic kilometre neutrino telescope |
The KM3NeT consortium, formed by 40 European astroparticle and sea science institutes, aims at developing a deep-sea research
infrastructure in the Mediterranean Sea hosting a multi-cubic-kilometre Cherenkov telescope for neutrinos with energies above
100GeV. In the past decade, the three founding collaborations of KM3NeT, ANTARES, NESTOR and NEMO, have developed the basic
technology and have intensively explored the properties of three candidate sites in the Mediterranean sea ranging from 2500m
to 4500m in depth. The EU-funded KM3NeT Design Study, started in February 2006, is now approaching the publication of a Technical
Design Report (TDR), where the technologies and the expected physics performance of the future detector are described in detail.
The EU funded Preparatory Phase for construction of the KM3NeT research facility has already started.
The location in the Mediterranean Sea will allow for surveying a large part of the Galactic Plane, including the Galactic Centre,
complementing the sky coverage of IceCube telescope and even improving the discovery potential in the same field of view.
In the deep-sea or deep-ice telescopes high-energy neutrinos are detected using the Cherenkov light from leptons and hadrons produced
in neutrino interactions with the matter in and surrounding the detector. Due to the low neutrino cross sections, the detection of
the fluxes expected from galactic and extragalactic sources requires to instrument large volumes of water or ice with photo-detectors
(photomultipliers). In the KM3NeT telescope, hundreds of instrumented Detection Units, each hosting tens of photo-sensors, will be
deployed several kilometres below sea level. The technical solutions developed during the Design Study and the KM3NeT design will be
presented and the expected KM3NeT telescope performance discussed. |
| Raymond Frey for the LIGO Scientific Collaboration and the Virgo Collaboration | Gravitational-wave transient detection and multi-messenger astrophysics | Astrophysical events which produce energetic emissions of electromagnetic radiation or neutrinos are also likely to be sources of gravitational waves (GW), which promise to provide unique insight into large-scale internal motions of the source system. The LIGO, GEO600, and Virgo GW detectors have been successfully constructed and operated at or exceeding their initial sensitivity targets. While these sensitivities have not yet been sufficient to yield a GW detection, meaningful constraints on sources have resulted from GW limits which are associated with gamma-ray detections from putative GRBs or magnetar flares. After discussing these results, we present current efforts to extend these associations to other "messengers" such as neutrinos, optical and radio, as well as development of other modes for incorporating GW transient searches in a full multi-messenger approach. We expect that the development of this approach may be crucial for fully exploiting the astrophysical potential of the era of advanced LIGO and Virgo GW detectors (about 2015) when we expect GW detections to be frequent. |
| Dave Besson |
| Speaker | Title | Abstract | |
| Sirin Odrowski | Neutrino point sources: Search strategies and results from IceCube |
In this talk I will present the latest results obtained in searches for neutrino point sources with the IceCube neutrino
telescope. In particular, the specific scenario of Galactic sources will be discussed. Depending on the assumed spectrum
and morphology of the source candidates, IceCube's sensitivity to neutrino point sources can be enhanced by using an
adequate search strategy or through the optimization of the cuts used to create the neutrino sample. Another promising
way to improve the performance of IceCube for soft spectra sources is the using IceCube and its smaller but more densely
instrumented predecessor AMANDA as a combined detector. Preliminary results of this novel search for Galactic neutrino point
sources will be presented. | |
| Jean-Pierre Ernenwein | The ANTARES deep-sea neutrino telescope | The ANTARES deep-sea neutrino telescope is located at a depth of 2475m in the Mediterranean Sea, close to Toulon, France. The detector comprises a three dimensional array of 885 photomultipliers, distributed on twelve detection lines. It is designed to detect the Cherenkov light produced by neutrino-induced muons passing close to the detector. Since June 2008 the construction of the detector is completed. During 2006-2007 the detector was operated in partial configurations. In this talk, preliminary results from a variety of analyses will be presented; the search for astrophysical point sources (steady and transient) in the Southern sky, a search for diffuse fluxes and a search for dark matter annihilation in the Sun. The prospects for the detection of exotic particles such as monopoles and nuclearites will also be discussed. | |
| Juan de Dios Zornosa | Point source search with the ANTARES neutrino telescope | Neutrino astronomy has particular advantages with respect to gammas and cosmic rays. Neutrinos are neutral and only interact weakly, so they are unique probes to study phenomena like AGNs, GRBs or SGR flares. The ANTARES telescope was completed in 2008 and is providing data which allow us to search for neutrino sources in the Southern sky. In this talk I will present the methods developed to look for these sources and the first results. | |
| Claudine Colnard | Status of IceCube-DeepCore: Sensitivity study for the Southern Hemisphere. |
The IceCube neutrino telescope is constructed to search for high energy neutrinos of cosmic origin. The detector site
at the South Pole is optimal to observe neutrinos from all regions of the sky. However, the aperture of the telescope
is limited to the Northern Hemisphere at energies below 1 PeV due to a predominant background of muons induced by cosmic
rays in the atmosphere.
We report in this talk about a singular approach to observe Galactic TeV-neutrino sources of the Southern Hemisphere
with IceCube. The compact Cherenkov detector IceCube-DeepCore at the bottom center of IceCube is used to enhance the
sensitivity of the telescope at low energies. | |
| Jairo Cavalcante de Souza | Indirect detection of supersymmetric particles with neutrino telescopes | Recent work has shown that neutrino telescopes can probe the supersymmetry breaking energy scale ($\sqrt{F}$). It was shown that NLSPs - originated in scenarios where the gravitino is the LSP - can be directly detected by these telescopes. In the case of NLSP detection, $\sqrt{F}$ will fall between 1e7 and 1e10 GeV. Here we analyze a complementary scenario ($\sqrt{F}$ between 1e5 and 1e7 GeV), where most of the NLSPs decay inside the Earth before reaching the detector. We describe our simulation of the tau lepton regeneration processes through the Earth and determine its flux at a detector such as IceCube. | |
| Nissim Fraija | Propagation of neutrinos through magnetized gamma-ray burst fireball |
The neutrino self-energy is calculated in a weakly magnetized plasma consists of electrons, protons,
neutrons and their anti-particles and using this we have calculated the neutrino effective potential
up to order M^(−4)_W . In the absence of magnetic field it reduces to the known result. We have
also calculated explicitly the effective potentials for different backgrounds which may be helpful in
different environments. By considering the mixing of three active neutrinos in the medium with the
magnetic field we have derived the survival and conversion probabilities of neutrinos from one flavor
to another and also the resonance condition is derived. As an application of the above, we considered
the dense and relativistic plasma of the Gamma-Ray Bursts fireball through which neutrinos of 5-30
MeV can propagate and depending on the fireball parameters they may oscillate resonantly or non-resonantly from
one flavor to another. These MeV neutrinos are produced due to stellar collapse or
merger events which trigger the Gamma-Ray Burst. The fireball itself also produces MeV neutrinos
due to electron positron annihilation, inverse beta decay and nucleonic bremsstrahlung. Using the
three neutrino mixing and considering the best fit values of the neutrino parameters, we found that
electron neutrinos are hard to oscillate to another flavors. On the other hand, the muon neutrinos
and the tau neutrinos oscillate with equal probability to one another, which depends on the neutrino
energy, temperature and size of the fireball. Comparison of oscillation probabilities with and without
magnetic field shows that, they depend on the neutrino energy and also on the size of the fireball.
By using the resonance condition, we have also estimated the resonance length of the propagating neutrinos as well
as the baryon content of the fireball. |
| Speaker | Title | Abstract |
| David Cerdeno | WIMP dark matter candidates | |
| Takeo Moroi | SuperWIMP dark matter | |
| Jason Kumar | TeV Probes of WIMPless Dark Matter | The recently proposed WIMPless dark matter scenario provides a dark matter candidate which can have a wide range of possible masses, while still retaining the naturally correct thermal relic density of the WIMP scenario. This scenario leads to possible detection signals which are quite different from those usually expected of WIMPs. We review the WIMPless dark matter scenario, and discuss novel signatures available at a variety of experiments, including the Tevatron, the LHC and IceCube/DeepCore. |
| Tracy Slatyer | The Sommerfeld enhancement for thermal relic dark matter with an excited state | Recent anomalies in direct and indirect detection experiments have motivated models of dark matter with nearly-degenerate excited states and Sommerfeld-enhanced annihilation at low velocities. I will present an accurate semi-analytic approximation for the Sommerfeld enhancement in models of inelastic dark matter with a single excited state, and outline the generic differences between this case and the elastic limit where the ground and excited states are degenerate. I will show the allowed annihilation rates in the local halo for models of this type that produce the correct relic abundance of dark matter, while satisfying constraints from measurements of the cosmic microwave background. |
| Carlos Yaguna | The inert doublet model of dark matter revisited | The inert doublet model, a minimal extension of the Standard Model by a second higgs doublet with no direct couplings to quarks or leptons, is one of the simplest and most appealing scenarios that can explain the dark matter. We show that, in this model, the annihilation of dark matter particles into three-body final states dominates, in a relevant portion of the viable parameter space, over those into two-body final states considered in previous analysis. As a result, the computation of the relic density is modified and the prospects for the direct and the indirect detection of inert higgs dark matter are significantly altered. In this letter, we derive the genuine viable parameter space of the inert doublet model, and we compute the correct direct detection cross section and annihilation branching ratios of inert higgs dark matter. |
| Speaker | Title | Abstract |
| Gordon Thomson | Results from the High Resolution Fly's Eye Experiment | |
| Yuichiro Tameda | Result from Telescope Array Experiment | |
| Andrew Taylor | The Heavy Nuclei Composition of Ultra High Energy Cosmic Rays | Utilising the recent (2009) Auger spectrum, Xmax, and RMS results, comparisons with cosmic ray nuclei propagation results are made. This leads to our determining what source injection parameters are needed for the best agreement with this complete data set. |
| Gwenael Giacinti | Propagation of UHECR heavy nuclei in the Galactic Magnetic Field |
The recent measurements of UHECR composition by the Pierre Auger Observatory show a shift towards heavy nuclei.
Most of the current litterature deals with protons or light nuclei.\
We investigate in this work the propagation of UHECR heavy nuclei, with E>60EeV, in different GMF models.
We compute the fractions of the sky in which UHECR sources would not be visible at Earth. We also investigate
magnified and demagnified regions. Finally, we look for images of potential astrophysical sources. |
| Antoine Calvez | The role of galactic sources and magnetic fields in forming the observed energy-dependent composition of ultrahigh-energy cosmic rays | Recent results from the Pierre Auger Observatory show an energy dependent chemical composition of ultrahigh-energy cosmic rays (UHECRs), with a growing fraction of heavy elements at high energies. These results suggest a possible non-negligible contribution from galactic sources. We show that in the case of UHECRs produced by gamma-ray bursts (GRBs), or by rare types of supernova explosions that took place in the Milky Way in the past; the change in the composition of the UHECRs can be the result of the difference in diffusion times between different species. The anisotropy in the direction of the Galactic Center is expected to be a few per cent on average, but the locations of the most recent/closest bursts can be associated with observed clustering of UHECRs. |
| Kumiko Kotera | Magnetars as sources of ultrahigh energy cosmic rays | We revisit the possibility that ultrahigh energy cosmic rays (UHECRs) are produced in the relativistic winds of rapidly rotating magnetars in light of the recent results of the Auger Observatory. Magnetars are believed to easily accelerate particles to the highest energies thanks to their strong magnetic fields and fast rotation periods that can induce voltage drops up to 10^22 V. However, the idea that they could be the progenitors of UHECRs had been somewhat abandoned as their very hard injection spectrum (Blasi et al. 00, Arons 03) made it difficult to fit the observed cosmic ray data. We demonstrate that the magnetar scenario can be reconciled with the observed cosmic ray spectrum when taking into account the distribution of magnetar rotation periods. We further investigate the possibility of iron being accelerated in these objects, and present estimates of the secondary gravitational wave signatures that one would expect from such sources. |
| Speaker | Title | Abstract |
| Kenji Shinozaki | Status of the JEM-EUSO Mission | The JEM-EUSO mission, onboard Japanese module of the International Space Station, is dedicated to the observation of ultra-high-energy cosmic rays (UHECRs) through the detection of the UV light associated with the giant air showers that they induce in the Earth atmosphere. The telescope is composed: i) of a large field-of-view optics based on Fresnel lenses, to cover an area of ~2 10^5 km^2 on the ground in Nadir mode, much larger than ground-based UHECR experiments, and ii) of a focal surface made of a very large number of highly sensitive photodetectors. The presentation will cover the scientific objectives of the mission and its development status, aiming at a launch in 2015. |
| Felix Aharonian | Angular, spectral and temporal features of highest energy protons and associated secondary gamma-rays and neutrinos propagating through the intergalactic radiation and magnetic fields | The angular, spectral and temporal features of the highest energy protons and accompanying secondary neutrinos and synchrotron gamma-rays propagating through the intergalactic radiation and magnetic fields are discussed based on the analysis of analytical solutions of the Boltzmann equation obtained in the limit of a small-angle approximation |
| Warren Essey | Cosmic Ray Astronomy with Secondary Gamma Rays and Neutrinos |
Active galactic nuclei are believed to be the sources of both gamma rays and
ultrahigh-energy cosmic rays. While the highest energy gamma rays from distant blazars must be attenuated and
filtered out by their interactions with the extragalactic background light, the cosmic rays can travel cosmological
distances without significant attenuation. These cosmic rays can interact with the background photons and produce
"secondary" gamma-rays and neutrinos along the line of sight. The secondary photons may have already been observed
by the Cherenkov telescopes, and the secondary neutrinos can be detected in ongoing observations by IceCube. The
combination of these secondary detections could help vastly improve models for the EBL, intergalactic magnetic field and
AGN dynamics. |
| Markus Ahlers | GZK Neutrinos after Fermi-LAT Diffuse Photon Flux | |
| Daniele Fargion | UHECR composition and Map versus UHE Tau Neutrino Astronomy | UHECR are probably Light nuclei. Their photodisintegration on CMBR will lead to PeV neutrino astronomy traces. To be observable in near future in Auger FD Heat and around TA telescopes. |
| Speaker | Title | Abstract |
| Beatriz Canadas | Indirect Search for Dark Matter with Fermi from the Galactic Center | |
| Celine Boehm | Can the morphology of gamma-ray emission distinguish annihilating from decaying dark matter? | The recent results from the PAMELA, ATIC, FERMI and HESS experiments have focused attention on the possible existence of high energy cosmic ray e+e- that may originate from dark matter annihilations or decays in the Milky Way. In this talk, I will present the morphology of the gamma-ray emission after propagation of the electrons generated by both annihilating and decaying dark matter models and discuss whether it is possible to distinguish the two types of candidates or not. |
| Sergio Palomares-Ruiz | Constraining Dark Matter Properties from a Gamma-Ray Detection | Most proposed dark matter candidates are stable and are produced thermally in the early Universe. However, there is
also the possibility of unstable dark matter, produced thermally or otherwise. We propose a strategy to distinguish between
dark matter annihilation and/or decay in the case that a clear signal is detected in gamma-ray observations of Milky Way
dwarf galaxies with gamma-ray experiments. The sole measurement of the energy spectrum of an indirect signal would render
the discrimination between these cases impossible. We show that by examining the dependence of the intensity and energy
spectrum on the angular distribution of the emission, the origin could be identified as decay, annihilation, or both.
In addition, once the type of signal is established, we show how these measurements could help to extract information
about the dark matter properties, including mass, annihilation cross section, lifetime, dominant annihilation and decay
channels, and the presence of substructure. I will also comment on signals from the Milky Way and the prospects to
constrain dark matter properties with experiments as Fermi. |
| Paolo Panci | Diffuse gamma ray constraints on annihilating or decaying Dark Matter after FERMI | We consider the diffuse gamma ray data from Fermi first year observations and compare them to the gamma ray fluxes predicted by Dark Matter annihilation or decay for different observation regions of the sky and a range of Dark Matter masses, annihilation/decay channels and Dark Matter galactic profiles. We find that the data exclude large regions of the Dark Matter parameter space not constrained otherwise and discuss possible directions for future improvements. Also, we further constrain Dark Matter interpretations of the e-e+ PAMELA/Fermi spectral anomalies, both for the annihilating and the decaying Dark Matter case: under very conservative assumptions, only models producing dominantly muons and assuming a cored Dark Matter galactic profile can fit the lepton data with masses around 2 TeV. |
| Miguel Angel Sanchez-Conde | Looking into the dark: the fingerprint of neutralinos and axions in gamma-rays | Despite our efforts, the dark matter (DM) nature still remains unveiled. Among the plethora of possible DM candidates, both neutralinos and axions are probably the preferred ones at present. Although with different properties, the search of both kind of particles can be done in gamma-rays with current experiments such as the Fermi satellite or Imaging Atmospheric Cherenkov telescopes (IACTs). In this talk, I will only focus on the sub-TeV domain and will briefly review the present status of neutralino searches with IACTs. In addition, I will discuss the importance of some experimental aspects as well as recent theoretical developments (e.g. the Internal Bremsstrahlung) for this kind of searches. On the other hand, the possible role of axion-like-particles in the DM game will be addressed as well; in this context, I will propose what could be a good observational strategy to be followed by IACTs in order to detect them in gamma-rays. |
| Brandon Hensley | Detectability and Spectrum of Annihilating Dark Matter Using Anisotropies in the Fermi Gamma-ray Background | The energy-dependence of the anisotropy (the anisotropy energy spectrum) of the large-scale isotropic diffuse gamma-ray background can reveal the presence of multiple contributing source populations. Annihilating dark matter in the substructure of the Milky Way halo could give rise to a modulation in the anisotropy energy spectrum of the diffuse gamma-ray emission measured by Fermi, enabling the detection of a dark matter signal. I will discuss the detectability of such a signal as a function of the assumptions on the blazar contribution to the background. Further, I will present novel methods of using a modulation in the anisotropy energy spectrum to disentangle a single source class from the remaining contributors to the background and discuss its possible applications to extracting a signal from dark matter annihilation. |
| Speaker | Title | Abstract |
| Matthieu Vivier | Searches for a DM annihilation signal toward dwarf spheroidal galaxies with VERITAS |
The VERITAS observatory, located in southern Arizona, is an array of four atmospheric Cherenkov telescopes designed for the detection of very high energy (VHE) gamma-rays above 100 GeV. Gamma-ray observations can be used to search for the signatures of annihilating dark matter (DM). VERITAS has recently focused its efforts in this direction on observations of dwarf spheroidal galaxies of the Local group. Dwarf spheroidal galaxies are potentially interesting targets for the detection of an annihilation signal due to their proximity and large DM content. A leading DM candidate is a weakly interacting massive particle (WIMP), which appears in many extensions of the standard model of particle physics. We report here on the observations of dwarf spheroidal galaxies with VERITAS, and discuss the results in the framework of WIMPs models. |
| Dan Hooper | Dark Matter Subhalos In the Fermi First Source Catalog | The Milky Way's dark matter halo is thought to contain large numbers of smaller subhalos. These objects can contain very high densities of dark matter, and produce potentially observable fluxes of gamma rays. In this article, we study the gamma ray sources in the Fermi Gamma Ray Space Telescope\\'s recently published First Source Catalog, and attempt to determine whether this catalog might contain a population of dark matter subhalos. We find that, while approximately 20-60 of the catalog\\'s unidentified sources could plausibly be dark matter subhalos, such a population cannot be clearly identified as such at this time. From the properties of the sources in the First Source Catalog, we derive limits on the dark matter\\'s annihilation cross section that are comparably stringent to those derived from recent observations of dwarf spheroidal galaxies. |
| Douglas Finkbeiner | Fermi Bubbles, the haze, and dark matter. | Gamma-ray observations by Fermi reveal two large gamma-ray lobes, extending to +- 50 degrees in latitude and +-20 degrees in longitude. The similarity of these structures to the WMAP haze indicate that they result from the same electron CR population. I will review the status of the observations, speculate about the origin of this signal, and suggest what it means for photon-based indirect dark matter searches in the inner Galaxy. |
| Greg Dobler | One Coin, Two Sides: the Microwave and Gamma-ray Haze | |
| Dmitry Malyshev | Gamma-ray Haze via Dark Matter and Millisecond Pulsars | Possible explanations for the haze of gamma-rays around the center of the Milky Way reported by Dobler et al are considered. It is found find that the most significant contributions may come from annihilating dark matter and millisecond pulsars. |
| Philipp Mertsch | Systematic effects in the extraction of the WMAP haze | The extraction of a `haze\\' from the WMAP microwave skymaps is based on subtraction of known foregrounds, viz. free-free (bremsstrahlung), thermal dust and synchrotron, each traced by other skymaps. While the 408 MHz all-sky survey is used for the synchrotron template, the WMAP bands are at tens of GHz where the spatial distribution of the radiating cosmic ray electrons ought to be quite different because of the energy-dependence of their diffusion in the Galaxy. The systematic uncertainty this introduces in the residual skymap is comparable to the claimed haze and can, for certain source distributions, even have a similar morphology and spectrum. Hence caution must be exercised in interpreting the haze as a signature of dark matter annihilation in the Galactic centre. |
| Speaker | Title | Abstract |
| Dimitrios Giannios | Understanding the ultrafast variability from blazars |
Recently two blazars (PKS 2155-304 and Mrk 501) have exhibited TeV flaring on timescales 1-2 orders of magnitude shorter that the light-crossing time of the host black holes. I discuss how these observations challenge our current paradigm for blazar emission and indicate that jet instabilities are the source of the ultrafast variability. A model of reconnection minijets forming inside the jet will be presented for the blazar variability. |
| Matthew Dalton | H.E.S.S. Unidentified Sources as Pulsar Wind Nebulae and HESS J1303-631 | In recent years, many extended unidentified gamma-ray sources have been discovered by H.E.S.S. at TeV energies in the Galactic plane. Many of these unidentified sources are without extended counterparts in X-rays or radio or with significantly less extended counterparts. Many of these sources now appear to be associated with pulsars which can be explained as such: pulsars emit a strong wind of high energy electrons which form a pulsar wind nebula (PWN). As the PWN ages, its magnetic field strength is expected to decrease as a result of the expansion, so that the lifetime of the TeV emitting particles increases accordingly. However, the radio and X-ray surface brightness is expected to decrease because of the reduction in the synchrotron surface brightness of the PWN. This scenario is explored within H.E.S.S. observations with special attention to the case of HESS J1303-631. |
| Jean-Marc Casandijan | Fermi LAT Observations of Galactic and Extragalactic Diffuse Emission on behalf of the Fermi-LAT Collaboration. |
The Large Area Telescope (LAT), one of two instruments on the Fermi Gamma-Ray Space Telescope, detects gamma-rays in the energy range of 20 MeV to 300 GeV and has been in routine operation for more than one year. Active galactic nuclei, pulsars, micro-quasars, and supernova remnants, for example, have been identified as sources of some of the LAT photons and have led to exciting new insights into the emission mechanisms of those objects. However, most of the photons detected by the LAT at GeV energies originate from the interstellar processes in the Galaxy. This high-energy gamma-ray emission comes from the interaction of cosmic-ray electrons and protons with the interstellar medium and radiation field. The LAT, with its large effective area and field of view as well as its survey-mode observation strategy and stable response, is particularly well suited for studying this emission and for providing informations on the cosmic rays and the distribution of gas and radiation in the Milky Way. For the first time, similar studies can be performed on other galaxies like the Magellanic Clouds and close starbursts galaxies. We provide an overview of the studies performed by the Fermi collaboration on the Galactic and extragalactic diffuse gamma-ray emission. It includes measurement of the gamma-ray emissivity spectrum of local gas, study of the gradient of cosmic-ray densities and N(H2) to W(CO) ratio and emission from local structures. We review also the diffuse emission of external galaxies and the LAT isotropic component related to the extragalactic diffuse gamma-ray emission. |
| Reshmi Mukherjee | Galactic Sources of Very High Energy Gamma-Ray Emission: Highlights from VERITAS | The VERITAS observatory, located in southern Arizona, consists of an array of four atmospheric Cherenkov telescopes for gamma-ray observations at energies above 100 GeV. After two and a half years of operation, VERITAS has detected emission from a variety of Galactic sources including shell-type supernova remnants (SNRs), pulsar wind nebulae (PWN), at least one X-ray binary system, and has also carried out a survey of the Cygnus region between 67 and 82 degrees in Galactic longitude, and -1 and 4 degrees in Galactic latitude, reaching an average VHE point-source flux sensitivity of better than 4% of the Crab Nebula flux at energies above 200 GeV. We will report on these results, in particular recent observations by VERITAS of PWN and SNRs. These objects, PWN in particular, comprise the bulk of known galactic TeV gamma-ray emitting objects. Studies at TeV energies are valuable for exploring the underlying energetic particle populations in these systems. |
| Giovanni Morlino | High energy emission from SNR RX J1713. |
Using a nonlinear theory for particle acceleration at shock waves in supernova remnants, we investigate the multi wavelength photon spectra produced by electrons and protons via several different emission processes.
The acceleration model includes magnetic field amplification and the self consistent computation of the maximum particle energy. The latter is a key parameter to understand the nature of TeV $\\\\gamma$-ray emission.
We compare the model with the observations of SNR RX J1713.7-3946 finding that the electron inverse Compton scattering cannot explain photon energies beyond ~ 1TeV, unless an unrealistically low background magnetic field is assumed. On the other hand $\\\\pi_0$ decay accounts very well for the TeV radiation if the proton spectrum extends up to $10^\{14\}$ eV.
The X-ray radiation observed by Suzaku is well fitted by the electron synchrotron emission if one assumes $K_\{ep\} \\\\sim 10^\{-4\}$ and a few $\\\\mu$Gauss background magnetic field. The resulting thickness of the X-ray emitting rims is also compatible with CHANDRA observations. |
| Speaker | Title | Abstract |
| Shin'ichiro Ando | Discovery of gamma-ray halos around active galactic nuclei and the first measurement of intergalactic magnetic fields | Magnetic fields in intergalactic space had not been measured until now, despite their importance for gamma-ray and cosmic-ray astronomy and their likely connection to the primordial fields that could have seeded the stronger magnetic fields observed in galaxies, Sun, and Earth. It has long been expected that intergalactic magnetic fields (IGMF) should cause the appearance of halos around the gamma-ray images of distant objects because an electromagnetic cascade initiated by a high-energy gamma-ray interaction with the photon background is broadened by the magnetic deflections. Here we report the discovery of gamma-ray halos in the stacked images of 170 brightest active galactic nuclei (AGN) in the 11-month source catalog of the Fermi Gamma-Ray Space Telescope. The dependence of the halo size and brightness on the gamma-ray energy and the source distance is consistent with IGMF, B = 10^\{-15\} G (\\\\lambda_B/1 kpc)^\{-1/2\} and \\\\lambda_B < 10-100 kpc, where B and \\\\lambda\ _B are the strength and correlation length of IGMF, respectively. The knowledge of IGMF will facilitate the future gamma-ray and charged-particle astronomy. Furthermore, since IGMF are likely to originate from the primordial seed fields created shortly after the Big Bang, this discovery opens a new window on the origin of cosmological magnetic fields, inflation, and the phase transitions in the early universe. |
| Rudy Gilmore | Cosmological Background Radiation and Extragalactic Gamma-ray Opacity |
Gamma rays traveling across extragalactic distances can be attenuated by electron-positron pair production interactions with the UV, optical, and IR extragalactic background light (EBL) originating from stars and AGN. I will discuss this phenomenon and our attempts to the model the EBL using models of galaxy emissivity, and will present new EBL calculations based on new semi-analytic models that use physically-motivated prescriptions for galaxy formation in a WMAP5 cold dark matter cosmology. Observations of distant blazars at GeV and TeV energies are affected by these processes, and the rapidly-growing field of extragalactic gamma-ray astronomy can provide constraints on structure formation. Also, GeV emission from gamma-ray bursts can potentially be a valuable probe of the high-redshift UV-optical background produced by early galaxies. I will present calculations of the evolving UV background and discuss the prospects of detecting evidence of attenuation due to these photons in gamma-ray burst spectra by satellite telescopes such as Fermi or by ground-based atmospheric Cherenkov telescopes. |
| Clementina Medina | Heavy jet for radiogalaxies | The well know radio-galaxy Cen A has been recently detected as a source of very high energy (VHE; E>100 GeV) γ-rays by the H.E.S.S. experiment just before Fermi/LAT detect it at high energies (HE; E>100 MeV). This detection, together with the M87\\'s one establish radiogalaxies as VHE γ-rays. Following these discoveries, we had developed a lepto-hadronic model for the VHE emission from the relativistic jets in sources as FR I radiogalaxies. We consider that the high energy emission is produced in a relativistic heavy jet launched by a dissipationless accretion disk. Protons and electrons are accelerated in a given compact region near the base of the jet, and they cool emitting multiwavelength radiation as they propagate along the jet. The proton and electron distributions are obtained through an inhomogeneous steady-state transport equation taken into account acceleration radiative and non-radiative cooling processes as well as particle transport by convecti on. The radiative output obtained in our model with an appropriate set of parameters can account for much of the observational data for both AGNs. Eventhough the flaring states of M87 can not be explained with this model, it allows for the possibility of explaining the stationary VHE emission by means of $pp$ interactions. The expected high-energy neutrino signal is also obtained and the possibility of detection with KM3NET and IceCube is discussed. |
| Quirin Weitzel | Recent Results from the MAGIC Telescopes | The current generation of Imaging Atmospheric Cherenkov Telescopes (IACTs) provides access to a large variety of very high energy (VHE, ca. 50 GeV to 50 TeV) gamma-ray sources in the universe. Since 2004, the MAGIC-I telescope located on the Canary island of La Palma is taking scientific data, accompanied since 2009 by a second telescope (MAGIC-II). They have a mirror diameter of 17m each, turning MAGIC into the IACT system with the lowest energy threshold: 40-50 GeV for observations at low zenith angles with the standard trigger and 20-25 GeV with the so-called sum-trigger. The two telescopes are operated in stereoscopic observation mode, which greatly increases the sensitivity of the instrument. Many important results have been achieved with MAGIC, including the detection of pulsed gamma-rays from the Crab pulsar and of gamma-ray emission from the high-redshift (z=0.536) Active Galactic Nucleus 3C279. In a joint multi-wavelength effort with other instruments, a str\
ong hint about the origin of VHE gamma-rays within the giant radio galaxy M87 was obtained. Just recently, a gamma-ray signal has been observed from IC310, which is the first head-tail radio galaxy detected in the VHE regime. In this talk, selected scientific highlights from MAGIC-I and the MAGIC stereo system will be presented and discussed. |
| Damiano Caprioli | Gamma-rays from heavy nuclei accelerated in supernova remnants |
Under the widely accepted hypothesis that supernova remnants are the main sources of the galactic cosmic rays, we study the acceleration of nuclei heavier than hydrogen in these environments. We show that accelerated heavy nuclei, besides having a dominant role in the shock dynamics, may be more relevant than protons in terms of the emission of gamma-rays due to the decay of the neutral pions produced in nuclear interactions. The observational consequences of this effect in the multi-wavelength emission from supernova remnants are also investigated. |
| Ievgen Vovk | Evidence for Strong Extragalactic Magnetic Fields from Fermi Observations of TeV Blazars | Magnetic fields in galaxies and galaxy clusters are produced via amplification of extremely weak \\"seed\\" magnetic fields of unknown nature. These seed fields, which might exist in their initial form in intergalactic medium, have escaped detection so far. Existing observational upper limits on the strength of the seed fields (~ 10^-9 G), which come from observations with radio telescopes, are much above typical theoretical predictions. Here we report a lower bound on the strength of magnetic fields in intergalactic medium, which stem from non-observation of GeV energy band emission from electromagnetic cascade initiated by multi-TeV gamma rays emitted by distant active galaxies and absorbed on their way through extragalactic medium. |
| Stephane Vincent | Production of TeV Gamma Radiation in the Vicinity of the Supermassive Black Hole | In the recent years radio-galaxies have emerged as a new class of extragalactic very-high energy gamma-ray emitters. Their proximity and well studied multi-wavelength behavior enable unique studies of the immediate surroundings of the supermassive black holes. Here, special attention is given to M87 and to the 2008 joined campaign pointing towards the immediate surrounding of the central black hole as origin of the VHE emission. We developped a Monte-Carlo simulation of particle acceleration around a supermassive black hole and show that the observed TeV gamma-ray emission from M87 can be explained by electrons accelerated in strong rotation-induced electric fields in vacuum gaps in the black hole magnetosphere. |
| Speaker | Title | Abstract |
| Timur Delahaye | Cosmic electron and positron fluxes at the Earth | Recent data on electron and positron cosmic rays (PAMELA, Fermi, ATIC, HESS) have risen a lot of interest in the last months as there exhibited discrepancies with the most popular prediction available then. I will explain our current understanding of Galactic cosmic rays and the way we manage to constrain the models. Though the constrain are quite good in reducing the uncertainties for protons and heavy ions, they leave us with large uncertainties concerning electrons and positrons. I will show that the actual precision of the data forces us to reconsider our simple models of cosmic rays. Actually if one properly takes into account the actual knowledge about propagation and sources of cosmic rays, it is natural to see features in the spectra detected at the Earth hence there is no reason to claim for a Dark Matter signal already. As a conclusion, I will consider other ways to look for Dark Matter signals in the sky. |
| Julien Lavalle | Indirect dark matter detection in light of high-resolution N-body simulation results | I will discuss the multi-messenger predictions that can be obtained by extrapolating the high-resolution N-body cosmological simulation results down to small subhalo mass scales. |
| Silvia Galli | Recombining the Universe with dark matter: constraints on self- annihilation cross sections. | I will show how it is possible to place sound constraints on DM self annihilation cross sections by making use of cosmological observables. Current CMB measurements do in fact allow the possibility to test DM self-annihilation down to the thermal values for particle masses of few GeV, and to place constraints that depend only on cosmological parameters. This kind of constraints, competitive at the quantitative level with galactic multimessenger ones, thus offer the qualitative advantage to be unplagued by astrophysical uncertainties typically correlated with structures. |
| Roland Crocker | Radio and gamma-ray constraints on dark matter annihilation in the Galactic center |
We determine upper limits on the dark matter (DM) self-annihilation cross section for scenarios in which annihilation leads to the production of electron--positron pairs. In the Galactic centre (GC), relativistic electrons and positrons produce a radio flux via synchroton emission, and a gamma ray flux via bremsstrahlung and inverse Compton scattering. On the basis of archival radio data, we have determined that the radio spectrum of a region ~ few degrees in extent around the GC is non-thermal over the range 74 MHz -- 10 GHz. We also consider gamma-ray data covering the same region from the EGRET instrument (about GeV) and from HESS (around TeV). We show how the combination of these data can be used to place robust constraints on DM annihilation scenarios, in a way which is relatively insensitive to assumptions about the magnetic field amplitude in this region. Our results are approximately an order of magnitude more constraining than existing Galactic centre radio and gamma ray limits. |
| Riccardo Catena | Thermal Relics in Modified Cosmologies: Bounds on Evolution Histories of the Early Universe from indirect dark matter searches. | Alternative cosmologies, based on extensions of General Relativity, predict modified thermal histories in the Early Universe in the pre Big Bang Nucleosynthesis (BBN) era, epoch which is not directly constrained by cosmological observations. When the expansion rate is enhanced with respect to the standard case, thermal relics typically decouple with larger relic abundances. The correct value of the relic abundance is therefore obtained for larger annihilation cross sections, as compared to standard cosmology. A direct consequence is that indirect detection rates are enhanced. We derive updated astrophysical bounds on the dark matter annihilation cross sections and use them to constrain alternative cosmologies in the pre-BBN era. |
| Ilias Cholis | Cosmic Ray Signals from Multiple States of Dark Matter | Recent data from cosmic ray experiments such as PAMELA, Fermi, ATIC all suggest the need for a new primary source of electrons and positrons at high (>~100 GeV) energies. Many proposals have been put forth to explain these data, usually relying on a single particle to annihilate or decay to produce e+e-. I will discuss about models with multiple species of WIMPs with significantly different masses. Such dark matter candidates chi_i annihilate into light bosons, they naturally produce equal annihilation rates, even as the available numbers of pairs for annihilation n_chi_i^2 differ by orders of magnitude. A consequence of these models can be to add additional signal naturally at lower (~100 GeV) versus higher (~ TeV) energies, changing the expected spectrum and even adding bumps at lower energies, which may alleviate some of the tension in the required annihilation rates between PAMELA and Fermi. These spectral changes may yield observable consequences in the microwave Haze signal observed with the Planck satellite. |
| Speaker | Title | Abstract |
| Pearl Sandick | Signatures of Dark Star Remnants in the Galactic Halo |
The very first stars likely formed from metal-free, molecular hydrogen-cooled gas at the center of dark matter minihalos. Prior to nuclear fusion, these stars may have been supported by dark matter heating from annihilations in the star. As the dark matter fuel supply became depleted, nuclear fusion and standard stellar evolution would have begun, and today the objects that began their lives as so-called Dark Stars would exist as a population of remnant intermediate mass black holes surrounded by dark matter spikes. Here we explore the signatures of dark matter annihilations in the dark matter spikes surrounding these black holes for a range of dark star formation scenarios, black hole masses, and dark matter annihilation modes. |
| Claes-Erik Rydberg | Observational constraints on Dark Stars with HST and JWST | The first stars in the history of the Universe are likely to form in the dense central regions of 10^5- 10^6 Msolar cold dark matter halos at a z of approximately 10-50. The annihilation of dark matter particles in these environments may lead to the formation of so-called dark stars. Dark stars are predicted to be cooler, larger, more massive and potentially more long-lived than conventional population III stars. We investigate the prospects of detecting high-redshift dark stars with the upcoming James Webb Space Telescope (JWST). We find that individual dark stars at z > 6 are intrinsically too faint to be detected by JWST. However, by exploiting foreground galaxy clusters as gravitational telescopes, certain varieties of cool (Teff below 30,000 K) dark stars should be within reach at redshifts up to a z of approximately 10. We will also argue that dark stars attaining masses in the 10^4-10^7 Msolar range should also be readily detectable with both the Hubble Space Telescope and ground-based 8-10 m class telescopes. Existing survey data already place strong constraints on 10^7 Msolar dark stars at a z of approximately 10. We show that such objects must be exceedingly rare or short-lived to have avoided detection. |
| Jan-Patrick H\¨ulss | Search for Neutrinos from the Dark Matter Halo of the Galaxy with IceCube |
The IceCube Neutrino Telescope at the geographic South Pole is sensitive to neutrinos from dark matter annihilations. Dark matter annihilations would result in an excess of neutrinos from regions with high concentrations of dark matter. An extended nearby source is the galactic halo. The neutrino flux from the galactic halo depends on the dark matter density and self annihilation cross section.
Two different approaches for the etection are presented: an observation of the outer Galaxy and of the Galactic Center region. Neutrinos from the outer Galaxy enter the IceCube detector after traveling through the Earth, which filters out cosmic ray produced muons. Thus, this signal is nearly background free. Neutrinos from the direction of the Galactic Center pass directly into the ice together with a huge amount of cosmic ray muons. Here, the separation is more challenging but the expected neutrino flux is larger than from the outer Galaxy.
We present recent IceCube limits on the self-annihilation cross-section of WIMPs with masses between 200 GeV and 10 TeV. |
| Matthias Danninger | Searches for Dark Matter Annihilations in the Sun and Earth with IceCube and DeepCore |
Dark matter could be indirectly detected through the observation of neutrinos produced as part of its self-annihilation process. Possible signatures are an excess neutrino flux from the Sun or the centre of the Earth, where dark matter could be gravitationally trapped. The recent commissioning of the full DeepCore sub-array, a low-energy extension of the IceCube neutrino observatory, offers exciting opportunities for neutrino physics in the energy region of 10 GeV to 1 TeV. DeepCore\\'s improved energy reach will, in particular, provide sensitivity to neutrinos from attractive WIMP candidates, like the neutralino or the lightest Kaluza-Klein particle (LKP), down to WIMP masses in the physically interesting region of about 50 GeV.
We present recent IceCube limits on muon neutrinos from dark matter annihilations in the Sun and Earth and resulting constraints on WIMP-proton cross-sections. Furthermore, we review the capabilities of the 2010 IceCube detector array with DeepCore for solar and terrestrial WIMP searches. |
| David Tran | Gamma-ray and neutrino signatures of unstable dark matter | We discuss complementary gamma-ray and neutrino tests of decaying dark matter interpretations of the recently observed leptonic cosmic-ray anomalies. In particular, we examine the angular profile of gamma-ray emission due to dark matter decay both from prompt radiation and inverse Compton scattering. We also analyze the capabilities of present and future neutrino observatories to detect or constrain the neutrino signatures that accompany leptonic dark matter decays. |
| Douglas Spolyar | Detecting Dark with IceCube | Recently, observations by PAMELA, the Fermi Gamma Ray Space Telescope (FGST), and other cosmic ray experiments have generated a great deal of interest in dark matter (DM) particles which annihilate at a high rate to leptons. The talk will explore the possibility of using large volume neutrino telescopes, such as IceCube, to constrain such models; specifically we consider signals due to DM annihilation in the inner Milky Way. We find that, if Dark Matter annihilations are responsible for the signals observed by PAMELA and FGST, then IceCube (in conjunction with the planned low threshold extension, DeepCore) should detect or exclude the corresponding neutrino signal from the inner Milky Way within a few years of observation. |
| Speaker | Title | Abstract |
| Genevieve Belanger | Interplay of Dark Matter and Collider physics | |
| Frederci Ronga | Particle Physics Data: Expectations for Direct Detection/Astrophysics | |
| D. Montanino | Conversion of TeV photons into axion-like particles in extragalactic magnetic fields | |
| Mattia Fornasa | Interpretation of Dark Matter particles with LHC and direct detection data | Both particle accelerators like the Large Hardon Collider (LHC) and Direct Detection (DD) experiments like CMDS or Xenon are currently exploited for the search of Dark Matter (DM). In the context of Weakly Interacting Massive Particles (WIMPs), I will show that a much better reconstruction of the DM properties can be obtained if the two techniques are considered at the same time and a simple ansatz is made, assuming that the WIMP local density $ \\\\rho_\\\\chi $ is proportional to the cosmological DM relic abundance $ (\\\\rho_\\\\chi/\\\\rho_\{DM\}) \\\\propto (\\\\Omega_\\\\chi/\\\\Omega_DM) $. I demonstrate this method in the case of a 24-parameter SUSY model with a neutralino LSP in the stau coannihilation region. Results show that a future ton-scale DD experiment will allow to break the degeneracies in the SUSY parameter space and achieve a better reconstruction of the neutralino composition and its relic density. |
| Eniko Regoes | Low-Scale GRavity Black Holes at LHC | We search for extra dimensions by looking for black holes at LHC. Theoretical investigations provide the basis for the collider experiments. We use black hole generators to simulate the experimental signatures (colour, charge, spectrum of emitted particles, missing transverse energy) of black holes at LHC in models with TeV scale quantum gravity, rotation, fermion splitting, brane tension and Hawking radiation. We implement the extra-dimensional simulations at the CMS data analysis and test further beyond standard models of black holes too. Cosmic neutrinos can produce black holes too leading to giant air showers detectable by Auger, Fermi-LAT. |
| Speaker | Title | Abstract |
| Damiano Caprioli | Non-linear diffusive shock acceleration and the supernova paradigm for galactic cosmic rays |
We discuss the implications of applying the non-linear diffusive shock acceleration theory to the calculation of the spectrum of galactic cosmic rays as produced in supernova remnants. The semi-analytic formalism we developed can account for the acceleration of particles from a thermal bath, their self-generation of magnetic turbulence, and the non-linear dynamical feedback of both relativistic particles and magnetic field on the shock dynamics. Most important, the total spectrum of injected cosmic rays is calculated as the convolution over time of the particles escaping during the Sedov phase and the adiabatically decompressed particles trapped in the expanding shell and released only at later times. We show how such a spectrum is well described by a power law in momentum with spectral index close to -4, despite the concave shape of the instantaneous spectra of accelerated particles. |
| Giovanni Morlino | Shock acceleration in partially ionized plasma |
We present the non-linear theory of shock acceleration applied to SNR expanding into partially ionized medium. In particular we investigate the role of ionization and charge-exchange processes. Using this heory we show how the Balmer lines detected from young SNR scan be used to test the efficiency of shocks in the production of cosmic rays. |
| Sergey Ostapchenko | Spectra of positrons and antiprotons from a time-dependent modeling of supernova remnants |
Energy spectra of cosmic rays and their secondaries produced in supernova remnants (SNR)
are calculated taking into account the time-dependence of the SNR shock. The production
of secondaries by accelerated cosmic rays is treated as a Monte Carlo process. The
obtained ratios of positron/electron and antiproton/proton spectra do not rise with energy,
staying at a few percent and few times 10^-5 level correspondingly. |
| Norita Kawanaka | Continuous and Multiple Injections of Cosmic Ray Electrons/Positrons from Nearby Pulsars and Their GeV-TeV Spectral Features |
We investigate the GeV-TeV spectrum of cosmic-ray electrons and positrons from astrophysical sources, especially pulsars, and the injections from continuous and/or multiple electron/positron sources. First, we find that a continuous injection from a single source produces a broad peak and a high energy tail above the peak in the observed electron spectrum, which can constrain the source duration. As for the case of multiple sources, we find that the average electron/positron spectrum predicted from nearby pulsars are consistent with PAMELA, Fermi and H.E.S.S. data. However, the ATIC/PPB-BETS peak around 500GeV is hard to produce by the sum of multiple pulsar contributions and requires a single (or a few) energetic pulsar(s). We also expect a large dispersion in the TeV spectrum due to the small number of sources, that may cause the high energy cutoff inferred by H.E.S.S. and potentially provide a smoking-gun for the astrophysical origin. These spectral diagnostic
s can be refined in the near future by the CALET/AMS-02 experiments to discriminate different
astrophysical and dark matter origins. The spectral signature of the electron/positron escape from the supernova remnant surrounding a pulsar is also discussed. |
| Speaker | Title | Abstract |
| Sihem Kalli | Bursting sources of ultra-high energy cosmic rays and inhomogenous extra-galactic magnetic fields. | The origin of ultra-high energy cosmic rays (UHECR) - particles with energy above 10^19 eV - remains one of the longest standing problems of astrophysics. The detected anisotropy in their arrival direction maps indicates that their sources follow the large scale structure (LSS) distribution. During their propagation, the UHECR could suffer deflections and time delay caused by the manetic field on large scales. We discuss a possible distortion of the maps of arrival directions that is associated with the inhomogeneous distribution of large scale magnetic fields. |
| Nathan Whitehorn | Icecube GRB Neutrino Search Results | Gamma-ray bursts are a prime candidate for acceleration of cosmic rays to the highest energies. Due to photopion production in these sources, acceleration of protons during the burst may be accompanied by simultaneous emission of high energy neutrinos. These neutrinos are expected to have energies in the TeV range, making them targets for detection by the Icecube antarctic neutrino observatory, which, beginning with the 2008-2009 season, has reached sensitivity at the levels of prevailing models. The Icecube collaboration has recently completed a GRB coincidence analysis of one year of data taken with half the final array during the 2008-2009 season. Results will be presented, as well as prospects for the 2009-2010 season and beyond. |
| Bouhou Boutayeb | Coincident searches for neutrinos and gravitational waves with the ANTARES and LIGO/VIRGO detectors for the GWHEN group [ANTARES & VIRGO/LIGO Coll.] | Cataclysmic cosmic events such as GRBs are plausible sources of gravitational waves (GW) and high-energy neutrinos (HEN). Both GW and HEN are alternative cosmic messengers that may escape very dense media and travel unaffected over cosmological distances. For this reason, such messengers could also reveal new or hidden sources that were not observed by conventional photon astronomy, such as the putative failed or choked GRBs.
With this poster we will present the strategies for coincident searches of GW and HEN from astrophysical sources (and GRBs in particular) that are currently developed by the ANTARES and VIRGO/LIGO collaborations within the GWHEN working group. |
| Seismic stellar diagnostic of the nature of dark matter | Jordi Casanellas & Ilidio Lopes | The annihilation of captured DM particles inside low-mass stars has been shown to change some of the stellar properties, such as the star's effective temperature, the time spent by the star in the main sequence, or the way the energy is transported throughout the star. In this poster we review these changes in the stellar evolution and we show that asteroseismology can be used to detect the presence of DM inside stars, as well as to differentiate between the various models of DM particles. |