Distinguishing dark matter from unresolved point sources in the Inner Galaxy with photon statistics

Samuel K. Lee, Mariangela Lisanti, Benjamin R. Safdi

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

Data from the Fermi Large Area Telescope suggests that there is an extended excess of GeV gamma-ray photons in the Inner Galaxy. Identifying potential astrophysical sources that contribute to this excess is an important step in verifying whether the signal originates from annihilating dark matter. In this paper, we focus on the potential contribution of unresolved point sources, such as millisecond pulsars (MSPs). We propose that the statistics of the photons - in particular, the flux probability density function (PDF) of the photon counts below the point-source detection threshold - can potentially distinguish between the dark-matter and point-source interpretations. We calculate the flux PDF via the method of generating functions for these two models of the excess. Working in the framework of Bayesian model comparison, we then demonstrate that the flux PDF can potentially provide evidence for an unresolved MSP-like point-source population.

Original languageEnglish (US)
Article number056
JournalJournal of Cosmology and Astroparticle Physics
Volume2015
Issue number5
DOIs
StatePublished - May 27 2015

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics

Keywords

  • dark matter experiments
  • gamma ray experiments
  • millisecond pulsars

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