title: Evidence for Unresolved γ-Ray Point Sources in the Inner Galaxy.
abstract: We present a new method to characterize unresolved point sources (PSs) generalizing traditional template fits to account for non-Poissonian photon statistics. We apply this method to Fermi Large Area Telescope γ-ray data to characterize PS populations at high latitudes and in the Inner Galaxy. We find that PSs (resolved and unresolved) account for ∼50% of the total extragalactic γ-ray background in the energy range ∼1.9 to 11.9 GeV. Within 10° of the Galactic Center with |b|≥2°, we find that ∼5%-10% of the flux can be accounted for by a population of unresolved PSs distributed consistently with the observed ∼GeV γ-ray excess in this region. The excess is fully absorbed by such a population, in preference to dark-matter annihilation. The inferred source population is dominated by near-threshold sources, which may be detectable in future searches.
authors.affiliation: Princeton Center for Theoretical Science, Princeton University, Princeton, New Jersey 08544, USA.|Broad Institute, Cambridge, Massachusetts 02142, USA.
authors.forename: Samuel K
authors.initials: SK
authors.lastname: Lee
authors.affiliation: Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Mariangela
authors.initials: M
authors.lastname: Lisanti
authors.affiliation: Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Safdi
authors.affiliation: Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Tracy R
authors.initials: TR
authors.lastname: Slatyer
authors.affiliation: Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Xue