Stringent and Robust Constraints on the Dark Matter Annihilation Cross
  Section From the Region of the Galactic Center
  For any realistic halo profile, the Galactic Center is predicted to be the
brightest source of gamma-rays from dark matter annihilations. Due in large
part to uncertainties associated with the dark matter distribution and
astrophysical backgrounds, however, the most commonly applied constraints on
the dark matter annihilation cross section have been derived from other
regions, such as dwarf spheroidal galaxies. In this article, we study Fermi
Gamma-Ray Space Telescope data from the direction of the inner Galaxy and
derive stringent upper limits on the dark matter's annihilation cross section.
Even for the very conservative case of a dark matter distribution with a
significant (~kpc) constant-density core, normalized to the minimum density
needed to accommodate rotation curve and microlensing measurements, we find
that the Galactic Center constraint is approximately as stringent as those
derived from dwarf galaxies (which were derived under the assumption of an NFW
distribution). For NFW or Einasto profiles (again, normalized to the minimum
allowed density), the Galactic Center constraints are typically stronger than
those from dwarfs.
