  Dark matter sterile neutrinos radiatively decay in the Milky Way, which can
be tested with searches for almost monochromatic photons in the X-ray cosmic
spectrum. We analyse the data of SRG/ART-XC telescope operated for two years in
the all-sky survey mode. With no significant hints in the Galactic diffuse
X-ray spectrum we explore models with sterile neutrino masses in 12-40 keV
range and exclude corresponding regions of sterile-active neutrino mixing.
