Structure Formation Models Weaken Limits on WIMP Dark Matter from Dwarf Spheroidal Galaxies

26 Aug 2020  ·  Ando Shin'ichiro, Geringer-Sameth Alex, Hiroshima Nagisa, Hoof Sebastian, Trotta Roberto, Walker Matthew G. ·

Dwarf spheroidal galaxies that form in halo substructures provide stringent constraints on dark matter annihilation. Many ultrafaint dwarfs discovered with modern surveys contribute significantly to these constraints... At present, because of the lack of abundant stellar kinematic data for the ultrafaints, non-informative prior assumptions are usually made for the parameters of the density profiles. Based on semi-analytic models of dark matter subhalos and their connection to satellite galaxies, we present more informative and realistic satellite priors. We show that our satellite priors lead to constraints on the annihilation rate that are between a factor of 2 and a factor of 7 weaker than under non-informative priors. As a result, the thermal relic cross section can at best only be excluded (with 95% probability) for dark matter masses of $\lesssim 40$ GeV from dwarf spheroidal data, assuming annihilation into $b\bar{b}$. read more

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Cosmology and Nongalactic Astrophysics High Energy Astrophysical Phenomena High Energy Physics - Phenomenology