2016/04/30 by Dan Hooper, Tim Linden, Alejandro Lopez · 1 citation
Physics and Astronomy · #astro-ph.CO #astro-ph.HE #hep-ph
paper · pdf · doi:10.1088/1475-7516/2016/08/019
17 pages, 6 figures
arxiv created 2016/08/08 · arxiv updated 2016/08/17
It has been suggested that unresolved radio galaxies and radio quasars (sometimes referred to as misaligned active galactic nuclei) could be responsible for a significant fraction of the observed diffuse gamma-ray background. In this study, we use the latest data from the Fermi Gamma-Ray Space Telescope to characterize the gamma-ray emission from a sample of 51 radio galaxies. In addition to those sources that had previously been detected using Fermi data, we report here the first statistically significant detection of gamma-ray emission from the radio galaxies 3C 212, 3C 411, and B3 0309+411B. Combining this information with the radio fluxes, radio luminosity function, and redshift distribution of this source class, we find that radio galaxies dominate the diffuse gamma-ray background, generating 77.2+25.4-9.4% of this emission at energies above ∼1 GeV. We discuss the implications of this result and point out that it provides support for scenarios in which IceCube's high-energy astrophysical neutrinos also originate from the same population of radio galaxies.