1 research outputs found
-factors for self-interacting dark matter in 20 dwarf spheroidal galaxies
Dwarf spheroidal galaxies are among the most promising targets for indirect
dark matter (DM) searches in -rays. The -ray flux from DM
annihilation in a dwarf spheroidal galaxy is proportional to the -factor of
the source. The -factor of a dwarf spheroidal galaxy is the line-of-sight
integral of the DM mass density squared times , where is the DM annihilation cross-section times relative velocity , angle brackets denote average over , and is the -independent
part of . If is
constant in , -factors only depend on the DM space distribution
in the source. However, if varies with , as in the presence of DM self-interactions, -factors also depend on
the DM velocity distribution, and on the strength and range of the DM
self-interaction. Models for self-interacting DM are increasingly important in
the study of the small scale clustering of DM, and are compatible with current
cosmological observations. Here we derive the -factor of 20 dwarf spheroidal
galaxies from stellar kinematic data under the assumption of Yukawa DM
self-interactions. -factors are derived through a profile Likelihood
approach, assuming either NFW or cored DM profiles. We also compare our results
with -factors derived assuming the same velocity for all DM particles in the
target galaxy. We find that this common approximation overestimates the
-factors by up to one order of magnitude. -factors for a sample of DM
particle masses, self-interaction coupling constants and density profiles are
provided electronically, ready to be used in other projects.Comment: 10 pages, 3 figures and 2 table