X-ray line signal from decaying axino warm dark matter

We consider axino warm dark matter in a supersymmetric axion model with R-parity violation. In this scenario, axino with the mass m (a) over tilde similar or equal to 7 keV can decay into photon and neutrino resulting in the X-ray line signal at 3.5 keV, which might be the origin of unidentified X-ray emissions from galaxy clusters and Andromeda galaxy detected by the XMM-Newton X-ray observatory. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.