Evidence for Unresolved γ-Ray Point Sources in the Inner Galaxy
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PhysRevLett.116.051103.pdf
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Author(s)
Lee, Samuel K.
Lisanti, Mariangela
Xue, Wei
Safdi, Benjamin
Slatyer, Tracy Robyn
Date Issued
February 2016
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Lee, Samuel K., Mariangela Lisanti, Benjamin R. Safdi, Tracy R. Slatyer, and Wei Xue. "Evidence for Unresolved γ-Ray Point Sources in the Inner Galaxy." Phys. Rev. Lett. 116, 051103 (February 2016). © 2016 American Physical Society
Version
Final published version
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.
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
Massachusetts Institute of Technology. Department of Physics
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.116.051103
