Components of the Extragalactic Gamma Ray Background
Abstract
We present new theoretical estimates of the relative contributions of unresolved blazars and star-forming galaxies to the extragalactic gamma-ray background (EGB) and discuss constraints on the contributions from alternative mechanisms such as dark matter annihilation and truly diffuse gamma-ray production. We find that the Fermi source count data do not rule out a scenario in which the EGB is dominated by emission from unresolved blazars, though unresolved star-forming galaxies may also contribute significantly to the background, within order-of-magnitude uncertainties. In addition, we find that the spectrum of the unresolved star-forming galaxy contribution cannot explain the EGB spectrum found by EGRET at energies between 50 and 200 MeV, whereas the spectrum of unresolved FSRQs, when accounting for the energy-dependent effects of source confusion, could be consistent with the combined spectrum of the low-energy EGRET EGB measurements and the Fermi-LAT EGB measurements.
Cite
@article{arxiv.1012.3678,
title = {Components of the Extragalactic Gamma Ray Background},
author = {Floyd W. Stecker and Tonia M. Venters},
journal= {arXiv preprint arXiv:1012.3678},
year = {2015}
}
Comments
version accepted for publication in the Astrophysical Journal