Analytic Approximations for the Velocity Suppression of Dark Matter Capture

Abstract Compact astrophysical objects have been considered in the literature as dark matter (DM) probes, via observational effects of annihilating captured DM. In this paper we investigate role stellar velocity on multiscatter-capture rates and find that capture DM by a star moving with respect to halo rest frame are suppressed predictable amount. We develop validate an analytical expression for rate suppression factor. This factor can be used directly reevaluate projected bounds DM–nucleon cross section, any given velocity, explicitly show using Population III stars probes. These (Population stars) particularly interesting candidates, since they form at high redshifts, very DM-density environments. previous results, obtained under assumption frame, essentially unchanged when considering possible orbital velocities those central stars.