Constraints on a Non-thermal History from Galactic Dark Matter Spikes
  In this paper we examine whether indirect detection constraints on dark
matter associated with a non-thermal history may be significantly improved when
accounting for the presence of galactic substructure in the form of dark matter
spikes. We find that significant constraints may be derived from the
non-observation of an excess of diffuse gamma-rays and from the properties of
bright gamma-ray point sources observed by the Fermi Gamma-Ray Space Telescope,
but these constraints depend sensitively on the details of the formation of the
first stars and their subsequent black hole remnants. However, we also find
that, especially if WIMPs annihilate primarily to quarks or gauge bosons, it is
possible to extract meaningful and conservative bounds on the annihilation
cross section.
