DIFFUSE γ-RAY EMISSION FROM MISALIGNED ACTIVE GALACTIC NUCLEI

M. Di Mauro, F. Calore, F. Donato, M. Ajello, L. Latronico
2013 Astrophysical Journal  
Active galactic nuclei (AGN) with jets seen at small viewing angles are the most luminous and abundant objects in the $\gamma$-ray sky. AGN with jets misaligned along the line-of-sight appear fainter in the sky, but are more numerous than the brighter blazars. We calculate the diffuse $\gamma$-ray emission due to the population of misaligned AGN (MAGN) unresolved by the Large Area Telescope (LAT) on the {\it Fermi} Gamma-ray Space Telescope ({\it Fermi}). A correlation between the $\gamma$-ray
more » ... n the $\gamma$-ray luminosity and the radio-core luminosity is established and demonstrated to be physical by statistical tests, as well as compatible with upper limits based on {\it Fermi}-LAT data for a large sample of radio-loud MAGN. We constrain the derived $\gamma$-ray luminosity function by means of the source count distribution of the radio galaxies (RGs) detected by the {\it Fermi}-LAT. We finally calculate the diffuse $\gamma$-ray flux due to the whole MAGN population. Our results demonstrate that the MAGN can contribute from 10% up to nearly the entire measured Isotropic Gamma-Ray Background (IGRB). We evaluate a theoretical uncertainty on the flux of almost an order of magnitude.
doi:10.1088/0004-637x/780/2/161 fatcat:ognll3t5pzgcnoqpg4mljesboa