Angular signatures of annihilating dark matter in the cosmic gamma-ray background

Journal Article · Sun Jun 15 04:00:00 EDT 2008 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.77.123518· OSTI ID:21205161

Cuoco, A; Brandbyge, J; Hannestad, S ^[1]; Haugboelle, T ^[1]; Miele, G ^[2]

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1. Department of Physics and Astronomy, University of Aarhus, Ny Munkegade, Bygnig 1520 8000 Aarhus (Denmark)
2. Universita 'Federico II', Dipartimento di Scienze Fisiche, Napoli, Italy and INFN Sezione di Napoli (Italy)

The extragalactic cosmic gamma-ray background (CGB) is an interesting channel to look for signatures of dark matter annihilation. In particular, besides the imprint in the energy spectrum, peculiar anisotropy patterns are expected compared to the case of a pure astrophysical origin of the CGB. We take into account the uncertainties in the dark matter clustering properties on subgalactic scales, deriving two possible anisotropy scenarios. A clear dark matter angular signature is achieved when the annihilation signal receives only a moderate contribution from subgalactic clumps and/or cuspy haloes. Experimentally, if galactic foreground systematics are efficiently kept under control, the angular differences are detectable with the forthcoming GLAST observatory, provided that the annihilation signal contributes to the CGB for a fraction > or approx. 10-20%. If, instead, subgalactic structures have a more prominent role, the astrophysical and dark matter anisotropies become degenerate, correspondingly diluting the dark matter signature. As complementary observables we also introduce the cross correlation between surveys of galaxies and the CGB and the cross correlation between different energy bands of the CGB, and we find that they provide a further sensitive tool to detect the dark matter angular signatures.

• OSTI ID: 21205161
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 12 Vol. 77; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANISOTROPY
ANNIHILATION
ASTROPHYSICS
BACKGROUND RADIATION
CORRELATIONS
COSMIC PHOTONS
ENERGY SPECTRA
GALAXIES
NONLUMINOUS MATTER