CAN THE EXCESS IN THE Fe XXVI Lyγ LINE FROM THE GALACTIC CENTER PROVIDE EVIDENCE FOR 17 keV STERILE NEUTRINOS?

Abstract

The standard model of particle physics assumes that neutrinos are massless, although adding non-zeros is required by the experimentally established phenomenon of neutrino oscillations requires neutrinos to have non-zero mass. Sterile neutrinos (or right-handed neutrinos) are a good warm dark matter candidate. We find that the excess of the intensity in the 8.7 keV line (at the energy of the FeXXVI Ly$\gamma$ line) in the spectrum of the Galactic center observed by the Suzaku X-ray mission cannot be explained by standard ionization and recombination processes. We suggest that the origin of this excess is via decays of sterile neutrinos with a mass of 17.4 keV and estimate the value of the mixing angle. The estimated value of the mixing angle $\sin^2(2\theta)=(4.1 \pm 2.2)\times10^{-12}$ lies in the allowed region of the mixing angle of dark matter sterile neutrino with a mass of 17-18 keV.