Sterile neutrino dark matter bounds from galaxies of the Local Group
  We show that the canonical oscillation-based (non-resonant) production of
sterile neutrino dark matter is inconsistent at $>99$% confidence with
observations of galaxies in the Local Group. We set lower limits on the
non-resonant sterile neutrino mass of $2.5$ keV (equivalent to $0.7$ keV
thermal mass) using phase-space densities derived for dwarf satellite galaxies
of the Milky Way, as well as limits of $8.8$ keV (equivalent to $1.8$ keV
thermal mass) based on subhalo counts of $N$-body simulations of M 31
analogues. Combined with improved upper mass limits derived from significantly
deeper X-ray data of M 31 with full consideration for background variations, we
show that there remains little room for non-resonant production if sterile
neutrinos are to explain $100$% of the dark matter abundance. Resonant and
non-oscillation sterile neutrino production remain viable mechanisms for
generating sufficient dark matter sterile neutrinos.
