Angular signatures of annihilating dark matter in the cosmic gamma-ray background
- Department of Physics and Astronomy, University of Aarhus, Ny Munkegade, Bygnig 1520 8000 Aarhus (Denmark)
- 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, Vol. 77, Issue 12; Other Information: DOI: 10.1103/PhysRevD.77.123518; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
Similar Records
Dark matter annihilation or unresolved astrophysical sources? Anisotropy probe of the origin of the cosmic gamma-ray background
Planck Lensing and Cosmic Infrared Background Cross-correlation with Fermi-LAT: Tracing Dark Matter Signals in the Gamma-Ray Background