Extracting limits on Dark Matter annihilation from gamma-ray
  observations towards dwarf spheroidal galaxies
  Dwarf spheroidal galaxies compose one of the most dark matter dominated
classes of objects, making them a set of targets to search for signals of dark
matter annihilation. Recent developments in gamma-ray astronomy, most
importantly the launch of the Fermi-LAT instrument, have brought those targets
into attention. Yet, no clear excess of gamma-rays has been confirmed from
these targets, resulting in some of the tightest limits on dark matter
annihilation from indirect searches. In extracting limits from dwarf spheroidal
galaxies, it is of great importance, to properly take into account all relevant
uncertainties. Those include the dark matter distribution properties of the
dwarf spheroidals and the uncertainties on the underlying background. We
revisit the limits on dark matter annihilation, from gamma-rays studying a set
of close-by dwarf spheroidal galaxies, for which, we have good understanding of
the uncertainties in the dark matter distribution. For those targets, we
perform and compare results for alternative methods in extracting the
background gamma-ray flux. This provides a method to discriminate among the
dark matter annihilation targets, those that can give robust constraints. We
finally present our tightest limits on dark matter annihilation, that come only
from the targets that ensure accurate understanding of both the gamma-ray
background and the dark matter distribution uncertainties.
