Fermi-LAT gamma-ray anisotropy and intensity explained by unresolved Radio-Loud Active Galactic Nuclei

Abstract

Radio-loud active galactic nuclei (AGN) are expected to contribute substantially to both the intensity and anisotropy of the isotropic gamma-ray background (IGRB). In turn, the measured properties of the IGRB can be used to constrain the characteristics of proposed contributing source classes. We consider individual subclasses of radio-loud AGN, including low-, intermediate-, and high-synchrotron-peaked BL Lacertae objects, flat-spectrum radio quasars, and misaligned AGN. Using updated models of the gamma-ray luminosity functions of these populations, we evaluate the energy-dependent contribution of each source class to the intensity and anisotropy of the IGRB. We find that collectively radio-loud AGN can account for the entirety of the IGRB intensity and anisotropy as measured by the Fermi Large Area Telescope (LAT). Misaligned AGN provide the bulk of the measured intensity but a negligible contribution to the anisotropy, while high-synchrotron-peaked BL Lacertae objects provide the dominant contribution to the anisotropy. In anticipation of upcoming measurements with the Fermi-LAT and the forthcoming Cherenkov Telescope Array, we predict the anisotropy in the broader energy range that will be accessible to future observations.

27 pages, 29 figures. This version matches the published version, minor changes only

References in corpus (11)

• Observations of the Crab Nebula with H.E.S.S
• The Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived From First-Year Fermi Large Area Telescope Data
• The Imprint of The Extragalactic Background Light in the Gamma-Ray Spectra of Blazars
• The Fermi-LAT high-latitude Survey: Source Count Distributions and the Origin of the Extragalactic Diffuse Background
• Star-forming galaxies as the origin of diffuse high-energy backgrounds: Gamma-ray and neutrino connections, and implications for starburst history
• The Starburst Contribution to the Extra-Galactic Gamma-Ray Background
• Dark matter annihilation or unresolved astrophysical sources? Anisotropy probe of the origin of cosmic gamma-ray background
• Cosmic Gamma-Ray Background from Star-Forming Galaxies
• Joint anisotropy and source count constraints on the contribution of blazars to the diffuse gamma-ray background
• Statistics of Cosmological Black Hole Jet Sources: Blazar Predictions for GLAST
• Anisotropy probe of galactic and extra-galactic Dark Matter annihilations

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• Tomographic imaging of the Fermi-LAT gamma-ray sky through cross-correlations: A wider and deeper look
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• Flat spectrum radio quasars and BL Lacs dominate the anisotropy of the unresolved gamma-ray background
• Can galactic dark matter substructure contribute to the cosmic gamma-ray anisotropy?
• The extragalactic $\gamma$-ray background: imprints from the physical properties and evolution of star-forming galaxy populations
• KiDS-Legacy: WIMP dark matter constraints from the cross-correlation of weak lensing and Fermi-LAT gamma rays
• Impact of model parameter degeneracy on leptonic radiation models. The case of blazar multi-wavelength spectra