2015

2015-12

http://arxiv.org/abs/1512.02943

Physical laboratory at the center of the Galaxy
V. I. Dokuchaev and Yu. N. Eroshenko

The Fermi-LAT space telescope reported an intriguing gamma-ray excess from the Galactic center with an angular size of several degrees, which cannot be explained by usual astrophysical sources but could be due to dark matter annihilation [35–44]. This result is still unreliable and requires additional checks. Presently, the search for the annihilation dark matter gamma rays is one of the “hot” points in astrophysics. The problem could be solved by the planned Russian GAMMA-400 gamma-ray space observatory [45].

[45] Galper A.M. et al., arXiv:1412.4239.

2015-11

http://arxiv.org/abs/1511.01018

Non-thermal Dark Matter Models and Signals

Hiroshi Okada, Yuta Orikasa, and Takashi Toma

We have shown the allowed parameter space of the DM annihilation cross section, the decay width of the metastable particle. As a feature of non-thermal DM discussed here, a strong indirect detection signal, especially sharp gamma-rays can be emitted due to internal bremsstrahlung. This would be a promising channel which is testable in future gamma-ray experiments such as CTA and GAMMA-400.

[39] A. M. Galper, O. Adriani, R. L. Aptekar, I. V. Arkhangelskaja, A. I. Arkhangelskiy, M. Boezio, V. Bonvicini and K. A. Boyarchuk et al., Adv. Space Res. 51, 297 (2013) [arXiv:1201.2490 [astro-ph.IM]].

2015-10

http://arxiv.org/abs/1510.07683

Cosmic rays: direct measurements

Paolo Maestro

GAMMA-400 is a next generation gamma-ray space observatory planned for 2023-2025 [110]. Though specifically designed to measure gamma-ray sources with unprecedented accuracy, the instrument also includes an innovative homogeneous and isotropic calorimeter made of cubic crystals, featuring a depth of 54 X0 or 2.5 lI when detecting laterally incident particles. The resulting improved shower containment and the large acceptance (a few m2sr) would allow to measure CR nuclei up to the "knee" with very good energy resolution.

[110] N.P. Topchiev et al., Pos(ICRC2015) 1026

2015-10

http://arxiv.org/abs/1510.03107

On the possibility to use semiconductive hybrid pixel detectors for study of radiation belt of the Earth

A. Guskov, G. Shelkov, P. Smolyanskiy, A. Zhemchugov

In parallel with monitoring of the radiation belt the Timepix detector could be a unique instrument for investigation of charged particles ux in the outer region the Earth's magnetosphere. Such data can be combined with an information about solar activity and an information from the magnetometer planned to be installed at "GAMMA-400".

[13] Topchiev N et al. 2015 arXiv:1507.06246

[14] Topchiev N et al. 2015 Bulletin of the Russian Academy of Sciences. Physics 79 3 417

2015-09

http://arxiv.org/abs/1509.03333

Minding the MeV Gap: the Indirect Detection of Low Mass Dark Matter

Kimberly K. Boddy and Jason Kumar

[14] A. M. Galper et al., (2014), arXiv:1412.4239 [physics.ins-det].

2015-09

http://arxiv.org/abs/1509.02672

Perspective of monochromatic gamma-ray line detection with the High Energy cosmic-Radiation Detection (HERD) facility onboard China's Space Station

Xiaoyuan Huang, Anna S. Lamperstorfer, Yue-Lin Sming Tsai, Ming Xu, Qiang Yuan, Jin Chang, Yong-Wei Dong, Bing-Liang Hu, Jun-Guang Lü, Le Wang, Bo-Bing Wu, Shuang-Nan Zhang

The next generation of space-borne high energy cosmic ray (CR) and γ-ray detectors, including the CALorimetric Electron Telescope (CALET), the DArk Matter Particle Explorer (DAMPE) and GAMMA-400 [15] are designed to perform very high energy resolution (~ 1% - 2%) detection of photons with large effective areas.

[15] A. Galper, V. Bonvicini, N. Topchiev, O. Adriani, R. Aptekar, et al. (2014), 1412.4239.

[18] A. Moiseev, A. Galper, O. Adriani, R. Aptekar, I. Arkhangelskaja, et al. (2013), 1307.2345.

2015-08

http://arxiv.org/abs/1508.07759

AMS tracking in-orbit performance

Martin Pohl

Several missions are approved and will be installed soon [18, 19, 15], more are in the planning phase [20].

[20] N.P. Topchiev et al., GAMMA-400 gamma-ray observatory, 34th International Cosmic Ray Conference, July 30 to August 6 2015, The Hague, The Netherlands, to be published in the proceedings

2015-08

http://arxiv.org/abs/1508.06276

First Observation of Time Variation in the Solar-Disk Gamma-Ray Flux with Fermi

Kenny C. Y. Ng, John F. Beacom, Annika H. G. Peter, Carsten Rott

Next-generation instruments, such as DAMPE [61], GAMMA-400 [62], and HERD [63], will allow the Sun to be monitored at the GeV range even beyond Fermi's lifetime.

[62] [GAMMA-400 Collab.], A. Galper et al., (2014), arXiv:1412.4239.

2015-08

http://arxiv.org/abs/1508.05827

Limits to dark matter properties from a combined analysis of MAGIC and Fermi-LAT observations of dwarf satellite galaxies

Javier Rico, Matthew Wood, Alex Drlica-Wagner, Jelena Aleksić, for the MAGIC Collaboration, the Fermi-LAT Collaboration

In the future, this analysis could include new instruments like CTA, Gamma-400 or Km3Net. Our global approach offers the best chances for indirect DM discovery, or for setting the most stringent limits attainable by these kinds of observations, therefore placing a new landmark in the field.

2015-08

http://arxiv.org/abs/1508.05190

Space- and Ground-Based Gamma-Ray Astrophysics

Stefan Funk

It should be noted, that the planned Russian/Italian space-mission Gamma-400 [173] aims to significantly improve the angular and energy resolution which might be relevant for line searches.

[173] Galper AM, et al. ArXiv e-prints (2013)

2015-08

http://arxiv.org/abs/1508.04418

Scalar Singlet Dark Matter and Gamma Lines

Michael Duerr, Pavel Fileviez Pérez, and Juri Smirnov

Therefore, if the low mass version of this model is realized in nature one can clearly observe a gamma line in near future at gamma ray telescopes such as Fermi-LAT [26] and the GAMMA-400 [28] experiments.

[28] N. P. Topchiev et al., "GAMMA-400 gamma-ray observatory," [arXiv:1507.06246 [astro-ph.IM]].

2015-08

http://arxiv.org/abs/1508.01425

Gamma Lines from Majorana Dark Matter

Michael Duerr, Pavel Fileviez Perez, Juri Smirnov

Future experimental searches for gamma lines are expected to have very good energy resolution, see for example the proposed GAMMA-400 [26]. Therefore, one could expect that this model can be tested or ruled out in the near future.

[26] N. P. Topchiev et al., arXiv:1507.06246 [astro-ph.IM]

2015-07
http://arxiv.org/abs/1507.06129

Towards a realistic astrophysical interpretation of the Galactic center excess
Daniele Gaggero, Marco Taoso, Alfredo Urbano, Mauro Valli, Piero Ullio

The additional source proposed here provides extra -ray emissivity also at energies larger than the GeV range analyzed in this work, although with a progressively smaller angular extent given that, due to the increase in the energy loss efficiency, electron diffusion is reduced on a shorter scale. This prediction can be tested in the near future, in the perspective of comparing low- and high-energy measurements by experiments such as ASTROGAM [47] and GAMMA-400 [48].
[48] N. P. Topchiev et al., Bull. Russ. Acad. Sci. Phys. 79, 417 (2015) [Izv. Ross. Akad. Nauk Ser. Fiz. 79, 454457 (2015)]

2015-07
http://arxiv.org/abs/1507.01475

On the Angular Resolution of the AGILE gamma-ray imaging detector
Sabatini S., Donnarumma I., Tavani M., et al.

It is interesting to note that the AGILE Tracker configuration is quite similar to the basic element of the gamma-ray instrument currently under study for the GAMMA-400 mission (Galper et al. 2013). The analog readout of a Silicon Tracker with AGILE-like characteristics is required to optimize the angular resolution with a thick converter (that in the case of GAMMA-400 is currently designed to be ~ 0.08 X° per plane).
Galper A.M. et al, 2013, Proceedings of the International Cosmic-Ray Conference 2013, Brazil, Rio de Janeiro, http://arxiv.org/ftp/arxiv/papers/1306/1306.6175.pdf

2015-06
http://arxiv.org/abs/1506.07522

Electro-Weak Dark Matter: non-perturbative effect confronting indirect detections
Eung Jin Chun and Jong-Chul Park

On the other hand, the Higgsino-like EWDM is excluded just for DM masses less than ~ 500 GeV and around Sommerfeld resonances. In near future, the remaining parameter regions for each EWDM will be probed by various upcoming cosmic-ray observation experiments such as CTA [27] and GAMMA-400 [28].
[28] A. M. Galper, V. Bonvicini, N.P. Topchiev, O. Adriani, R.L. Aptekar, I.V. Arkhangelskaja, A.I. Arkhangelskiy and L. Bergstrom et al., arXiv:1412.4239 [physics.ins-det].

2015-06
http://arxiv.org/abs/1506.05107

Simplified Dirac Dark Matter Models
Michael Duerr, Pavel Fileviez Perez, and Juri Smirnov

We have investigated carefully the final state radiation and the gamma lines in this model using a Gaussian distribution to model the detector resolution. Unfortunately, in this type of models is very difficult to distinguish the gamma lines from the continuum spectrum coming from final state radiation. In the future one could have a very good energy resolution in experiments such as GAMMA-400 [31–33] and one can investigate this issue in more detail.
[31] N. P. Topchiev, A. M. Galper, V. Bonvicini, O. Adriani, R. L. Aptekar, I. V. Arkhangelskaja, A. I. Arkhangelskiy and L. Bergstrom et al., “The GAMMA-400 experiment: Status and prospects,” Bull. Russ. Acad. Sci. Phys. 79 (2015) 3, 417.
[32] A. M. Galper, V. Bonvicini, N. P. Topchiev, O. Adriani, R. L. Aptekar, I. V. Arkhangelskaja, A. I. Arkhangelskiy and L. Bergstrom et al., “The GAMMA-400 space observatory: status and perspectives,” arXiv:1412.4239 [physics.ins-det].
[33] A. M. Galper, O. Adriani, R. L. Aptekar, I. V. Arkhangelskaja, A. I. Arkhangelskiy, M. Boezio, V. Bonvicini and K. A. Boyarchuk et al., “Status of the GAMMA-400 Project,” Adv. Space Res. 51 (2013) 297 [arXiv:1201.2490 [astro-ph.IM]].

2015-06
http://arxiv.org/abs/1506.05104

Strong support for the millisecond pulsar origin of the Galactic center GeV excess
Richard Bartels, Suraj Krishnamurthy, and Christoph Weniger

Furthermore, since most of the sources contributing to the GCE are likely just below the observational threshold, upcoming gamma-ray observations with improved angular resolution (Fermi pass 8 data, or planned/proposed gamma-ray satellites like GAMMA-400 [37], ASTROGAM and PANGU [38]) should enable us to detect many more of these sources and to study their distribution.
[37] N. Topchiev, A. Galper, V. Bonvicini, O. Adriani, R. Aptekar, et al., Bull.Russ.Acad.Sci.Phys. 79, 417 (2015).

2015-06
http://arxiv.org/abs/1506.03474

Miguel Perez Torres, et al.
The Spanish Square Kilometer Array White Book

GeV facilities (see [13] and references therein). The AGILE and Fermi satellites are currently continuously scanning the sky in the _100 MeV to 300 GeV energy range. While AGILE will probably stop operations before the early science phase of SKA, Fermi will likely continue operating through 2020 and potentially beyond, with both survey and pointed observations. In the future the GAMMA-400 mission, planned for launch in 2021, will explore the sky in the 100 MeV up to 3000 GeV energy range in pointing mode, but reaching about an order of magnitude improvement in angular and energy resolution over Fermi at energies of 100 GeV. Therefore, detailed HE gamma-ray observations of known and newly identified sources should lead to a significant progress in our understanding of particle acceleration processes, which could be complemented with SKA ones already in the early science phase.

2015-05
http://arxiv.org/abs/1505.04380

Is it possible to discover a dark matter particle with an accelerator?
Vadim A. Bednyakov

Simultaneously, one looks for more massive (TeV-scale) particles, which could be difficult to detect directly, because one should expect much smaller number density of them to fit current DM density. The gamma-ray astronomy has no such a limitation. The international Cherenkov Telescope Array (CTA) with more than 100 ground-based dedicated telescopes is planned to capture Cherenkov light ashes from -rays scattered by the atmosphere. The CTA will be able to measure gamma-rays with 100-TeV energy, which could be generated by annihilations or decays of DM with 100-TeV scale masses. This energy scale reaches the highest limit on the DM mass expected from fundamental physics arguments [25]. With GAMMA-400 [46] gamma-ray telescope one expects new results in the energy range 0.1-3000 GeV [47-50].
[46] P. Cumani, A. Galper, V. Bonvicini, N. Topchiev, O. Adriani, et al., The GAMMA-400 Space Mission, arXiv:1502.0297.

2015-05
http://arxiv.org/abs/1505.06055

Gamma rays from the Galactic Centre Region: a review
Christopher van Eldik
Next generation gamma-ray instruments like the GAMMA-400 space mission [220] and the ground-based Cherenkov Telescope Array (CTA, [221]) will provide the necessary performance to mark a significant step forward in Galactic Centre astrophysics and dark matter searches, but also in high-energy astroparticle physics in general. Compared to existing instruments, both gamma-ray telescopes will significantly improve in sensitivity, energy coverage, and energy as well as angular resolution. CTA, for which construction of a first partial array may start already in 2016, will cover an energy range from several 10 GeV to more than 100 TeV. In its core energy range, it will outperform existing IACTs by a factor ~ 10 better flux sensitivity as well as improved angular resolution. The space-born GAMMA-400 instrument, currently planned for launch in 2019, will provide a smaller effective area than Fermi-LAT, but at the same time significantly improve in cosmic ray background rejection, and outperform Fermi-LAT by a large factor both in angular and energy resolution.
A. M. Galper, et al., Proc. 33rd ICRC (Rio de Janeiro) arXiv:1306.6175.

2015-04
http://arxiv.org/abs/1504.05187

Monochromatic Gamma Rays from Dark Matter Annihilation to Leptons

Adam Coogan, Stefano Profumo, and William Shepherd

HESS-II, GAMMA-400 and CTA line searches are only expected to tighten these constraints by an order of magnitude [35], and so will not be able to probe line signals from AMS-fitting points in these theories.

2015-04
http://arxiv.org/abs/1504.04024

Indirect Detection of Dark Matter Using MeV-Range Gamma-Ray Telescopes

Kimberly K. Boddy and Jason Kumar

The most recent searches with gamma-ray satellites1 have been performed by the Fermi-LAT [3-5]. The upcoming space-based telescope GAMMA-400 [6] is set to launch in 2018 and will have an energy range that overlaps with Fermi and extends up to 3 TeV.

[6] GAMMA-400 Collaboration, "The GAMMA-400 space observatory: status and perspectives," arXiv:1412.4239 [physics.ins-det].

2015-04
http://arxiv.org/abs/1504.01726

Physics at the e⁺e^- Linear Collider

G. Moortgat-Pick, et al.

An example of the second type of goal has been provided in the recent past by the multi-messenger constraints on the dark matter interpretation of the PAMELA positron fraction "rise" (where the relevance of the point just made clearly manifested) or, at present, by the tentative hint for a ~ 130GeV "gamma-ray line" [1250]. For this kind of task, statistics helps a lot but it is clearly not enough. Crosschecks and tests with different techniques and possibly improved resolutions are needed. Fortunately, current (HESS) or planned (CTA) IACTs may provide such a tool. This is also an arena where the proposed satellite experiment GAMMA-400 [1251] might contribute, thanks to its superior resolution (see e.g. [1252])

[1251] A. M. Galper, O. Adriani, R. L. Aptekar, I. V. Arkhangelskaja, A. I. Arkhangelskiy, M. Boezio, V. Bonvicini and K. A. Boyarchuk et al., Adv. Space Res. 51 (2013) 297.

2015-04
http://arxiv.org/abs/1503.06348

WIMP searches with gamma rays in the Fermi era: challenges, methods and results

Jan Conrad, Johann Cohen-Tanugi, Louis E. Strigari

On a longer time scale (2018 and beyond), two other experiments will probe the high- energy electromagnetic sky: GAMMA-400 and HERD. GAMMA-400 is a Russian-led satellite observatory, planned for launch in 2018-2019. Building upon the successes of Fermi and AGILE, it features a gamma ray telescope reminiscent of the LAT, supplemented with a Konus-FG gamma ray burst monitor. The baseline design covers the range from 100 MeV to 10 TeV and is optimized for best performance around 100 GeV, where a very deep electromagnetic calorimeter (25 radiation lengths compared to ~ 8.5 for the LAT), associated with a silicon strip tracker, will provide excellent energy and angular resolutions at such energies (a factor ten better angular resolution at 100 GeV than either DAMPE or CALET, and comparable energy resolution). Among the various gamma ray and cosmic ray science topics, dark matter searches, and especially the hunt for gamma ray lines, are a prime focus of the science case (Galper et al., 2013a; Moiseev et al., 2013). Further information on the GAMMA-400 design and science case can be found in Galper et al. (2013a,b).

Galper, A. M., Adriani, O., Aptekar, R. L., et al., in American Institute of Physics Conference Series, American Institute of Physics Conference Series, Vol. 1516, edited by J. F. Ormes (2013) pp. 288-292, arXiv:1210.1457 [astro-ph.IM] .

Galper, A. M., Adriani, O., Aptekar, R. L., et al., Advances in Space Research 51, 297 (2013b), arXiv:1201.2490 [astro-ph.IM] .

Moiseev, A. A., Galper, A. M., Adriani, O., et al., ArXiv e-prints (2013), arXiv:1307.2345 [astroph.IM] .

2015-03
http://arxiv.org/abs/1503.04860
On conservative models of “the pair-production anomaly” in blazar spectra at Very High Energies
T.A. Dzhatdoev
Future instruments with high sensitivity, (e.g. CTA [56]), or with good angular resolution, such as emulsion gamma-ray telescope [57] or the GAMMA-400 detector [58], would be able to employ the same method as [55] to put more tight constraints on the EGMF strength.
[58] Galper A M et al. (GAMMA-400) 2013 AIPCP 1516 288

2015-03
http://arxiv.org/abs/1503.01500
Signatures of Majorana dark matter with t-channel mediators
M. Garny, A. Ibarra, S. Vogl
The next-generation of gamma ray telescopes GAMMA-400 [42] and especially CTA [43], will improve the limits by a factor of a few, depending on the energy, as shown in Fig. 6, lower plots.
[42] A. Galper, O. Adriani, R. Aptekar, I. Arkhangelskaja, A. Arkhangelskiy et al., Adv.Space Res. 51 (2013) 297, arXiv:1201.2490.

2015-02
http://arxiv.org/abs/1502.04294
Satio Hayakawa and dawn of high-energy astrophysics in Japan
Jun Nishimura
Figure 25: GAMMA-400 detector layout [42]. Inside bracket shows the expected launching year.
[42] A.M. Galpar et al., arXiv 1306.6175.

2015-01
http://arxiv.org/abs/1501.05957
Dark Matter Constraints on Composite Higgs Models
Nayara Fonseca, Renata Zukanovich Funchal, Andre Lessa, Laura Lopez-Honorez
The Fermi-LAT telescope, which is studying the gamma-ray flux from multiple astrophysical sources, has provided the first strong exclusion limits on DM annihilation cross-sections excluding (?ann v) ~ 3?10-26 cm3/s for candidates with masses up to ~ 100 GeV for a 100% annihilation into bb [8, 9]. It is very likely that new data will soon be available with e.g. AMS-02 for antimatter cosmic rays, Ice-Cube for neutrinos, HESS-II for gamma-rays and with a new generation of experiments, such as GAMMA-400 and the CTA.

2015-01
http://arxiv.org/abs/1501.00259
Cascade Model of an Anomaly in Blazar Spectra at Very High Energy
Timur Dzhatdoev
Future instruments with either high sensitivity (e.g. CTA [25]) or extremely good angular resolution (e.g. emulsion gamma-ray telescope [26] or the GAMMA-400 apparatus [27]) would possibly allow to measure the EGMF strength.
[27] A.M. Galper et al. (GAMMA-400), AIPCP, 1516, 288 (2013)