Where to find a dark matter sterile neutrino?
  We propose a strategy of how to look for dark matter (DM) particles possessing a radiative decay channel and derive constraints on their parameters from observations of X-rays from our own Galaxy and its dwarf satellites. When applied to the sterile neutrinos in keV mass range, it allows a significant improvement of restrictions to its parameters, as compared with previous works. 
A. Boyarsky, A. Neronov, O. Ruchayskiy, M. Shaposhnikov, I. Tkachev