Conservative constraints on dark matter annihilation into gamma rays

Abstract

Using gamma-ray data from observations of the Milky Way, Andromeda (M31), and the cosmic background, we calculate conservative upper limits on the dark matter self-annihilation cross section to monoenergetic gamma rays, σAv γγ, over a wide range of dark matter masses. (In fact, over most of this range, our results are unchanged if one considers just the branching ratio to gamma rays with energies within a factor of a few of the endpoint at the dark matter mass.) If the final-state branching ratio to gamma rays, Br(γγ), were known, then σAv γγ/Br(γγ) would define an upper limit on the total cross section; we conservatively assume Br(γγ) 10-4. An upper limit on the total cross section can also..