Evidence for Unresolved Gamma-Ray Point Sources in the Inner Galaxy

24 Aug 2015, 16:30


Particle Cosmology Theory and Experiment Particle Cosmology


Benjamin Safdi (massachusetts institute of technology)


We present a new method to characterize unresolved point sources (PSs), which generalizes traditional template fits to account for non-Poissonian photon statistics. Using Fermi Large-Area Telescope gamma-ray data, we use the method to characterize PS populations at high latitudes and in the Inner Galaxy. We find that PSs (resolved and unresolved) account for $\sim$50% of the total extragalactic gamma-ray background in the energy range $\sim$1.9 to 11.9 GeV.Within 10$^\circ$ of the Galactic Center (with $|b| > 2^\circ$), we find that $\sim$5% of the flux is accounted for by unresolved PSs; the observed $\sim$GeV gamma-ray excess near the Galactic Center is preferentially absorbed by an unresolved PS template as compared to a dark-matter template.

Primary author

Benjamin Safdi (massachusetts institute of technology)


Mariangela Lisanti (Stanford University) Dr Samuel Lee (Princeton University) Tracy Slatyer

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