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Title: Radio galaxies dominate the high-energy diffuse gamma-ray background

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.
 [1] ;  [2] ;  [3]
  1. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Univ. of Chicago, Chicago, IL (United States)
  2. The Ohio State Univ., Columbus, OH (United States)
  3. Univ. of Michigan, Ann Arbor, MI (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
FERMILAB-PUB-16-128-A; arXiv:1604.08505
Journal ID: ISSN 1475-7516; 1452788
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2016; Journal Issue: 08; Journal ID: ISSN 1475-7516
Institute of Physics (IOP)
Research Org:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States