The sensitivity of Cherenkov telescopes to dark matter and astrophysical anisotropies in the diffuse gamma-ray background

Abstract

In this article, the capability of present (H.E.S.S., MAGIC, VERITAS) and planned (CTA) ground-based Cherenkov telescope systems for detecting angular anisotropies in the diffuse gamma-ray background is investigated. Following up on a study of the impact of instrumental characteristics (effective area, field of view, angular resolution, and background rejection efficiency), the first part examines the influence of different observational strategies, i.e. whether a single deep observation or a splitting over multiple shallow fields is preferred. In the second part, the sensitivity to anisotropies generated by self-annihilating dark matter is studied for different common dark matter models. We find that a relative contribution of ~10% from dark matter annihilation to the extra-galactic diffuse gamma-ray background can be detected with planned configurations of CTA. In terms of the thermally-averaged self-annihilation cross section, the sensitivity of CTA corresponds to values below the thermal freeze-out expectation <sigma v> = 3 x 10-26 cm3s-1 for dark matter particles lighter than ~200 GeV. We stress the importance of constraining anisotropies from unresolved astrophysical sources with currently operating instruments already, as a novel and complementary method for investigating the properties of TeV sources.

27 pages, 6 figures, 2 tables; v2: new paragraphs and figures added. Improvements in clarity of the text and readability of the figures. Conclusions unchanged. Matches published version on JCAP

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Cited by in corpus (14)

• The nature of the Diffuse Gamma-Ray Background
• Sensitivity Projections for Dark Matter Searches with the Fermi Large Area Telescope
• The angular power spectrum of the diffuse gamma-ray emission as measured by the Fermi Large Area Telescope and constraints on its Dark Matter interpretation
• WIMP searches with gamma rays in the Fermi era: challenges, methods and results
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• The CTA aims at the Inert Doublet Model
• Unveiling the Gamma-ray Source Count Distribution Below the Fermi Detection Limit with Photon Statistics
• Statistical Measurement of the Gamma-ray Source-count Distribution as a Function of Energy
• Complementarity of Dark Matter Searches at Resonance
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• Can galactic dark matter substructure contribute to the cosmic gamma-ray anisotropy?
• Observing small-scale $\gamma$-ray anisotropies with the Cherenkov Telescope Array