Constraints on decaying Dark Matter from XMM-Newton observations of M31

Understand

We derive constraints on parameters of the radiatively decaying Dark Matter (DM) particles, using XMM-Newton EPIC spectra of the Andromeda galaxy (M31).

• Using the observations of the outer (5'-13') parts of M31 we improve the existing constraints.
• For the case of sterile neutrino DM, combining our constraints with the latest computation of abundances of sterile neutrino in the Dodelson-Widrow (DW) scenario, we obtain the lower mass limit m_s < 4 keV, which is stronger than the previous one m_s < 6 kev, obtained recently by Asaka et al.
• (2007) [hep-ph/0612182].