Search for Dark Matter Annihilation in Galaxy Groups

We use 413 weeks of publicly available Fermi Pass 8 gamma-ray data combined with recently developed galaxy group catalogs to search for evidence of dark matter annihilation in extragalactic halos. In our study, we use luminosity-based mass estimates and mass-to-concentration relations to infer the J...

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Bibliographic Details
Main Authors: Lisanti, Mariangela (Author), Mishra-Sharma, Siddharth (Author), Rodd, Nicholas Llewellyn (Contributor), Safdi, Benjamin Ryan (Contributor)
Other Authors: Massachusetts Institute of Technology. Center for Theoretical Physics (Contributor), Massachusetts Institute of Technology. Department of Physics (Contributor)
Format: Article
Language:English
Published: American Physical Society, 2018-04-19T18:32:50Z.
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Summary:We use 413 weeks of publicly available Fermi Pass 8 gamma-ray data combined with recently developed galaxy group catalogs to search for evidence of dark matter annihilation in extragalactic halos. In our study, we use luminosity-based mass estimates and mass-to-concentration relations to infer the J factors and associated uncertainties for hundreds of galaxy groups within a redshift range z≲0.03. We employ a conservative substructure boost factor model, which only enhances the sensitivity by an O(1) factor. No significant evidence for dark matter annihilation is found, and we exclude thermal relic cross sections for dark matter masses below ∼30  GeV to 95% confidence in the bb[over ¯] annihilation channel. These bounds are comparable to those from Milky Way dwarf spheroidal satellite galaxies. The results of our analysis increase the tension but do not rule out the dark matter interpretation of the Galactic Center excess. We provide a catalog of the galaxy groups used in this study and their inferred properties, which can be broadly applied to searches for extragalactic dark matter.
United States. Department of Energy (Contract DESC00012567)
United States. Department of Energy (Contract DESC0013999)