Angular power spectrum of gamma-ray sources for GLAST: blazars and clusters of galaxies

Abstract

Blazars, a beamed population of active galactic nuclei, radiate high-energy gamma-rays, and thus are a good target for the Gamma Ray Large Area Space Telescope (GLAST). As the blazars trace the large-scale structure of the universe, one may observe spatial clustering of blazars. We calculate the angular power spectrum of blazars that would be detected by GLAST. We show that we have the best chance of detecting their clustering at large angular scales, θ>~ 10 deg, where shot noise is less important, and the dominant contribution to the correlation comes from relatively low redshift, z <~ 0.1. The GLAST can detect the correlation signal, if the blazars detected by GLAST trace the distribution of low-z quasars observed by optical galaxy surveys, which have the bias of unity. If the bias of blazars is greater than 1.5, GLAST will detect the correlation signal unambiguously. We also find that GLAST may detect spatial clustering of clusters of galaxies in gamma-rays. The shape of the angular power spectrum is different for blazars and clusters of galaxies; thus, we can separate these two contributions on the basis of the shape of the power spectrum.

14 pages, 10 figures; added references; accepted by MNRAS

Cited by in corpus (14)

• Gamma Ray Signals from Dark Matter: Concepts, Status and Prospects
• Dipoles in the Sky
• Joint anisotropy and source count constraints on the contribution of blazars to the diffuse gamma-ray background
• Anisotropy probe of galactic and extra-galactic Dark Matter annihilations
• Cross-Correlation of Cosmic Shear and Extragalactic Gamma-ray Background: Constraints on the Dark Matter Annihilation Cross-Section
• Tomography of the Fermi-LAT gamma-ray diffuse extragalactic signal via cross-correlations with galaxy catalogs
• 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
• Angular Signatures of Annihilating Dark Matter in the Cosmic Gamma-Ray Background
• Angular Anisotropies in the Cosmic Gamma-ray Background as a Probe of its Origin
• Constraining Dark Matter in Galactic Substructure
• Planck Lensing and Cosmic Infrared Background Cross-Correlation with Fermi-LAT: Tracing Dark Matter Signals in the Gamma-Ray Background
• Can the morphology of gamma-ray emission distinguish annihilating from decaying dark matter?
• Characterising the signatures of star-forming galaxies in the extra-galactic $\gamma$-ray background
• Dark Matter and Galaxy Cross-Correlations with the Cherenkov Telescope Array Observatory