Isotropic diffuse and extragalactic $\gamma$-ray background: emission from extragalactic sources vs dark matter annihilating particles

Abstract

The isotropic diffuse $\gamma$-ray background (IGRB) has been detected by various experiments and recently the Fermi-LAT Collaboration has precisely measured its spectrum in a wide energy range. The origin of the IGRB is still unclear and we show in this paper the significative improvements that have been done, thanks to the new Fermi-LAT catalogs, to solve this mystery. We demonstrate that the $\gamma$-ray intensity and spectrum of the IGRB is fully consistent with the unresolved emission from extragalactic point sources, namely Active Galactic Nuclei and Star Forming Galaxies. We show also that the IGRB can be employed to derive sever constraints for the $\gamma$-ray emission from diffuse processes such as annihilation of Dark Matter (DM) particles. Our method is able to provide low bounds for the thermal annihilation cross section for a wide range of DM masses.

6 pages, 5 figures. Proceedings of the XIV International Conference on Topics in Astroparticle and Underground Physics (TAUP 2015), 7-11 September 2015, Torino, Italy

References in corpus (5)

• The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV
• The Origin of the Extragalactic Gamma-Ray Background and Implications for Dark-Matter Annihilation
• Composition of the Fermi-LAT isotropic gamma-ray background intensity: Emission from extragalactic point sources and dark matter annihilations
• Diffuse gamma-ray emission from galactic pulsars
• A simplified view of blazars: contribution to the X-ray and gamma-ray cosmic backgrounds