2012

2012-12

http://arxiv.org/abs/1212.6087

Gamma-ray evidences of the dark matter clumps

K. Belotsky, A. Kirillov, M. Khlopov

Also we discuss possibilities when gamma-radiating clump changes visibly its position on celestial sphere and it is seen as a spatially extended gamma-source (EGS), what can be probed in future experiments like Gamma-400.

In principle, such values can be reached for Gamma-400 detector [62] at some energy interval.

[62] A.M. Galper et al. Status of the GAMMA-400 Project.ArXiv: astro-ph.IM/1201.2490, January 2012.

2012-11

http://arxiv.org/abs/1211.7090

Galactic Searches for Dark Matter

Louis E. Strigari

Even extending beyond Fermi-LAT, Gamma-400, a Russian space-based mission that is designed to detect gamma rays in the energy range of 100 MeV to 3 TeV (Galper et al., 2012), will complement the above results.

Galper, A., Adriani, O., Aptekar, R., Arkhangelskaja, I., Arkhangelskiy, A., et al., 2012. Design and Performance of the GAMMA-400 Gamma-Ray Telescope for the Dark Matter Searches.

2012-11

http://arxiv.org/abs/1211.6739

The 130GeV gamma-ray line and generic dark matter model building constraints from continuum gamma rays, radio and antiproton data

Masaki Asano,TorstenBringmann,GünterSigl,and Martin Vollmann

It will thus be exciting to await experiments with improved energy resolution and/or statistics like, GAMMA-400 [66] or HESS-II [67], that will be able to distinguish between the peculiar spectrum of internal bremsstrahlung and a monochromatic line [26].

[66] A.M. Galper, O. Adriani, R.L. Aptekar, I.V. Arkhangelskaja, A.I. Arkhangelskiy, M. Boezio, V. Bonvicini, K.A. Boyarchuk et al., AIP Conf. Proc. 1516, 288 (2012) [arXiv:1210.1457 [astro-ph.IM]].

2012-11

http://arxiv.org/abs/1211.3116

Dark Matter and Indirect Detection in Cosmic Rays

Jonathan L. Feng

At present, much activity and excitement surrounds a tentative line signal at E_γ ≈ 135 GeV [27]. The required annihilation cross section to explain this signal is very large, but models with such large signals existed even before the anomaly was reported [28, 29], and, of course, many more have been constructed since. Further progress to determine if the line signal is real and to improve sensitivities for both continuum and line searches is sure to come from continued running of existing experiments and upcoming experiments, including HESS-2, HAWC, CTA, DAMPE, GAMMA-400, HERD, as well as AMS-02 and CALET.

2012-11

http://arxiv.org/abs/1211.1534

TPC in -ray astronomy above pair-creation threshold

D. Bernard

A TPC might well be a first layer of an otherwise high-energy (0.1 GeV - 3 TeV) range project such as Gamma-400 [28].

[28] A.M. Galper et al., "Status of the GAMMA-400 Project," arXiv:1201.2490 [astro-ph.IM].

2012-10

http://arxiv.org/abs/1210.4392

Searches for Particle Dark Matter with gamma-rays

Jan Conrad

This gain in sensitivity is naturally accompanied by a number of detection claims or indications, the most recent being the claim of a line feature at a dark matter particle mass of ∼ 130 GeV at the Galactic Centre, a claim which requires confirmation from the Fermi-LAT collaboration and other experiments, for example HESS II or the planned Gamma-400 satellite.

[51] A.M. Galper, R.L. Aptekar, I.V. Arkhangelskaya, M. Boezio, V. Bonvicini, B.A. Dolgoshein, M.O. Farber, M.I. Fradkinet al., NuovoCim. C 034N3 (2011) 71.

2012-10

http://arxiv.org/abs/1210.4161

Review of Indirect WIMP Search Experiments

CarstenRott

In the future GAMMA-400 [53] with an effective area of 4 m², an angular resolution of (~0.01° at E_γ =100 GeVand an energy resolution of 1% could surpass Fermi-LAT. GAMMA-400 could be launched as early as 2018.

[53] A.M. Galper et al., arXiv:1201.2490 [astro-ph.IM].

2012-10

http://arxiv.org/abs/1210.3852

Unidentified sources in the Fermi-LAT second source catalog: the case for DM subhalos

Hannes-S.Zechlin, Dieter Horns

As a final remark, a potential successor of Fermi-LAT such as GAMMA-400 [93, 94] will significantly improve the observable energy range (100 MeV - 3 TeV), angular resolution (~0.01° at 100 GeV), and energy resolution (~1% at 100 GeV). The launch of GAMMA-400 is planned for 2018. For the case of unidentified Fermi-LAT sources, such a telescope will constrain their celestial position with enhanced precision.

[93] A.M. Galper, O. Adriani, R.L. Aptekar, et al., Status of the GAMMA-400 Project, ArXiv e-prints (2012) [arXiv:1201.2490].

[94] A.M. Galper, O. Adriani, R.L. Aptekar, et al., Design and Performance of the GAMMA-400 Gamma-Ray Telescope for the Dark Matter Searches, ArXiv e-prints (2012)[arXiv:1210.1457].

2012-09

http://arxiv.org/abs/1209.3015

Stringent and Robust Constraints on the Dark Matter Annihilation Cross Section From the Region of the Galactic Center

Dan Hooper^1;2, Chris Kelso^1;3, and Farinaldo S. Queiroz^1;4

Looking toward the future, we find very promising the possibility of the post-Fermi gamma-ray satellite, GAMMA-400 [54]. As GAMMA-400's overall effective area and acceptance will be comparable to that of Fermi, it will likely not be more sensitive to dark matter annihilations from flux-limited sources, such as dwarf galaxies. With considerable improvements in both angular and energy resolution relative to Fermi, however, GAMMA-400 should be able to much better separate astrophysical backgrounds in the inner Galaxy from any dark matter annihilation signal that is present.

[54] L. Bergstrom, G. Bertone, J. Conrad, C. Farnier and C. Weniger, arXiv:1207.6773 [hep-ph].

2012-09

http://arxiv.org/abs/1209.1373

MATTERS OF GRAVITY

The newsletter of the Topical Group on Gravitation of the American Physical Society, Number 40, Fall 2012

Dark Matter News: Tentative Evidence of a 130 GeV Gamma-Ray Line from Dark Matter Annihilation at the Fermi Large Area Telescope

Katherine Freese, University of Michigan

This result is as yet tentative. Since it is based on only 50 photons, further data will be required, both from FERMI and from other upcoming gamma-ray experiments such as HESS-II, CTA, and GAMMA-400 [13]. In addition, the result has not yet been vetted by the FERMI collaboration. Puzzling is also the fact that another 130 GeV line appears in the direction of the bright limb at Earth's horizon, dominantly produced by cosmic ray showers in the atmosphere; this cannot be explained by a dark matter signal. While it is encouraging that such a line is not seen throughout the data, e.g. not in the Galactic Plane away from the GC, still these limb events are perplexing. It will be very interesting to see whether this tentative hint of a 130 GeV gamma-ray line towards the Galactic Center persists over the next few years.

[13] L. Bergstrom, G. Bertone, J. Conrad, C. Farnier and C. Weniger, arXiv:1207.6773 [hep-ph].

2012-08
Physical Review D 86, 103514 (2012)

http://arxiv.org/abs/1208.6082

The 130 GeV Fingerprint of Right-handed Neutrino Dark Matter

Lars Bergström

FIG. 3: The γ-ray differential energy results (multiplied by E²) for a 135 GeV right-handed neutrino dark matter candidate are shown, with the present Fermi-LAT energy resolution ΔE/E = 10% FWHM (solid black line), with a factor of 2 improvement (red dashed line) and with a future γ-ray instrument, such as GAMMA-400 [39] (dash-dotted blue line) with resolution at the one percent level. The extrapolated power-law ~E^-2.6 of the presently measured continuous γ- ray background is also shown.

[39] A.M. Galper, O. Adriani, R.L. Aptekar,I.V. Arkhangelskaja, A.I. Arkhangelskiy, M. Boezio,V. Bonvicini, K.A. Boyarchuk et al., arXiv:1201.2490[astro-ph.IM].

2012-08

http://arxiv.org/abs/1208.5897

Multi messenger astronomy and CTA: TeV cosmic rays and electrons

PiergiorgioPicozza^a,b, MirkoBoezio^c

A similar calorimetry approach will be employed by the Gamma-400 [74] experiment. This experiment is aimed to study the high-energy gamma-ray flux and cosmic-ray electrons and nuclei. The apparatus will be placed on board a Russian satellite, which launch is foreseen for 2017-2018. With a similarly deep but significantly larger calorimeter (acceptance of about 1 m2sr), Gamma-400 should be able to extend the cosmic-ray measurements performed by CALET.

[74] A.M. Galper, et al., arXiv:1201.2490, 2012.

2012-08
Dark Universe 1 (2012) 194-217

http://arxiv.org/abs/1208.5481

Gamma Ray Signals from Dark Matter: Concepts, Status and Prospects

TorstenBringmann^a, ChristophWeniger^b

[24] A. Galper et al., (2012), 1201.2490;

[25] N. Topchiev, private communication;

[26] A. Galper et al., (2012), 1210.1457.

2012-08

http://arxiv.org/abs/1208.1406

Chemical Composition of Galactic Cosmic Rays with Space Experiments

MirkoBoezio, EmilianoMocchiutti

This will be the main scientific goal of future satellite-born experiments such as CALET [76] and Gamma-400 [77] that will have the energy resolution and acceptance to precisely probe the high energy (100s GeV-TeV) region.

[77] A.M. Galper, et al., Astrophys. Space Sci. Trans. 7 (2011) 75.

2012-08

http://arxiv.org/abs/1208.0828

Are Lines From Unassociated Gamma-Ray Sources Evidence For Dark Matter Annihilation?

Dan Hooper^{1, 2} and Tim Linden³

Additionally, the Gamma-400 instrument promises a significant improvement in both the angular and energy resolution, which will enable a detailed comparison between the tentative line feature and the continuum emission predicted in dark matter scenarios [47].

[47] A. Galper et. al. arXiv:1201.2490 [[astro-ph.IM]

2012-07

http://arxiv.org/abs/1207.6773

Investigating Gamma-Ray Lines from Dark Matter with Future Observatories

Lars Bergström, Gianfranco Bertone, Jan Conrad, Christian Farnier, ChristophWeniger

We found that only GAMMA-400, thanks to a claimed energy resolution of about 1.5% at 100 GeV, will be able to separate a γγ line from a Zγ or Hγ, if the corresponding branching ratio is comparable to that into two photons, whileHESS-II and CTA cannot separate them.

[19] A.M. Galper, O. Adriani, R.L. Aptekar, I.V. Arkhangelskaja, A.I. Arkhangelskiy, M. Boezio, V. Bonvicini, K.A. Boyarchuket al., arXiv:1201.2490 [astro-ph.IM].

2012-06

9th Workshop on Science with the New Generation of High Energy Gamma-ray Experiments
From high energy gamma sources to cosmic rays, one century after their discovery
20-22 June 2012 , Lecce (Italy), 4.8 Мб 

2012-06

http://arxiv.org/abs/1206.2595

Constraining very heavy dark matter using diffuse backgrounds of neutrinos and cascaded gamma rays

KohtaMurase^1,2 and John F. Beacom^1,2,3

Although the precise determination of the VHE DGB is obviously required and other interpretations are also possible, significant impacts on understanding dark matter and the DGB are expected if the VHE Excess is confirmed. Such the optimistic scenario is also interesting because they are testable for some parameters. In the Galactic scenario, dark matter masses of m_dmc²~3-30 TeV are necessary to explain the VHE DGB. Although the neutrino background is below the atmospheric background, the case of leptonic channels is testable by IceCube within a few years. On the other hand, in the VHDM-induced cascade scenario, extremely heavy masses (≥ 10 PeV) are required. Since large neutrino fluxes are predicted, such exotic cases are already excluded by neutrino observations. Those results demonstrate the importance of neutrino detectors such as IceCube and KM3Net for testing the properties of dark matter. Of course, deeper observations by Fermi and future detectors such as GAMMA-400 [95] should also provide us with crucial information.

[95] A.M. Galper, O. Adriani, R.L. Aptekar, I.V. Arkhangelskaja, A.I. Arkhangelskiy, M. Boezio, V. Bonvicini and K.A. Boyarchuk et al., arXiv:1201.2490 [astro-ph.IM].

2012-05

http://arxiv.org/abs/1205.4882

Dark Matter Evidence, Particle Physics Candidates and Detection Methods

Lars Bergström

However, an interesting player has recently entered the dark matter indirect detection scene. This is the Russian-Italian project GAMMA-400 [111], which has a launch around 2018 approved and is planned with a slightly smaller effective area than Fermi-LAT, but with better angular resolution and in particular better energy resolution than that of Fermi-LAT by an order of magnitude. This would take the search for dark matter to another level of sensitivity. If the present indication of a line signal would persist, it should be seen in GAMMA-400 with a significance of the order of 10σ.

[111] A.M. Galper, O. Adriani, R.L. Aptekar, I.V. Arkhangelskaja, A.I. Arkhangelskiy, M. Boezio, V. Bonvicini, K.A. Boyarchuk et al., arXiv:1201.2490 [astro-ph.IM].

2012-05

http://arxiv.org/abs/1205.4700

Spectral and spatial variations of the diffuse gamma-ray background in the vicinity of the Galactic plane and possible nature of the feature at 130 GeV

Alexey Boyarsky^a,b, Denys Malyshev^b, Oleg Ruchayskiy^c

Additional observations with HESS-2, Gamma-400 and CTA will probably be required in order to check these models (see [22]), but until that the DM interpretation of 130 GeV feature and treating all other features in a different way looks dubious.

[22] L. Bergstrom, G. Bertone, J. Conrad, C. Farnier and C. Weniger, Investigating Gamma-Ray Lines from Dark Matter with Future Observatories, 1207.6773.

2012-04

AGILE 9th Science Workshop: 
"Astrophysics with AGILE: five years of surprises", April 16 and 17, 2012, Frascati (Italy), 2.5 Мб 

2012-02

http://arxiv.org/abs/1202.1454

Special Issue on Proceedings of the 25th International Symposium on Lepton-Photon Interactions at High Energies (Lepton-Photon 2011) - Part II, v. 79, no. 5, pp. 1021-1043 (2012). Indirect Searches for Dark Matter

Indirect Searches for Dark Matter: a status review

MarcoCirelli^a,b

In general, some of our best hopes for clarifying the situation lie in the FERMI satellite itself, of which the prelaunch predicted sensitivities [107] let us believe that a DM with thermal cross section will be probed at 3σ up to a mass of several tens or even hundreds of GeV, depending on the annihilation channel and the chosen target. Another set of upcoming experiments will further improve the sensitivity on -ray lines, e.g. HESS-II which will soon be operational, CTA which should start in a few years and Gamma-400 which is being advocated for. In the merit of the 130 GeV line signal, they will provide precious information [108].

[108] L. Bergstrom, G. Bertone, J. Conrad, C. Farnier and C. Weniger, arXiv:1207.6773 [hep-ph].

2012-02

http://arxiv.org/abs/1202.1170

Saas-Fee Lecture Notes: Multi-messenger Astronomy and Dark Matter

Lars Bergström

Detection of a gamma-rate line signal would need a detector with very good energy resolution, like one percent or better. This is not achieved by FERMI (although data on a line search have been presented [87]). However, the Russian satellite GAMMA-400 [88] seems to have very promising characteristics for this type of dark matter search, when it is launched by the end of this decade. This could be a very interesting new instrument in the search for gamma-ray lines from annihilation (or decay) of dark matter.

Unfortunately, for most models the branching ratio for this channel is too small to be measurable with present day energy resolution, and we will drop it from now on. (This may however change when the high-resolution instrument GAMMA-400 [88] is operational towards the end of this decade. This is specified to have an energy resolution of 1%, which will be a perfect instrument for searching for γlines from annihilation, and also from models where dark matter decays radiatively [172].)

[88] A. M. Galper, et al., Astrophys. Space Sci. Trans. 7, 75 (2011).