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arXiv · 1009.1912

Dark-matter decays and Milky Way satellite galaxies

Annika H. G. Peter·Andrew J. Benson
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Abstract

We consider constraints on a phenomenological dark-matter model consisting of two nearly degenerate particle species using observed properties of the Milky Way satellite galaxy population. The two parameters of this model, assuming the particle masses are >~ GeV, are v_k, the recoil speed of the daughter particle, and tau, the lifetime of the parent particle. The satellite constraint that spans the widest range of v_k is the number of satellites that have a mass within 300 pc M300 > 5 x 10^6 solar masses, although constraints based on M300 in the classical dwarfs and the overall velocity function are competitive for v_k >~ 50 km/s. In general, we find that tau <~ 30 Gyr is ruled out for 20 km/s <~ v_k <~ 200 km/s, although we find that the limits on tau for fixed v_k can change constraints by a factor of ~3 depending on the star-formation histories of the satellites. We advocate using the distribution of M300 in Milky Way satellites determined by next-generation all-sky surveys and follow-up spectroscopy as a probe of dark-matter properties.

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Annika H. G. Peter, Andrew J. Benson. 2010-09-09. Dark-matter decays and Milky Way satellite galaxies. https://doi.org/10.1103/physrevd.82.123521

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