Heating of the intergalactic medium by the radiative decay of neutrinos

Assuming that there exists a species of heavy sterile neutrinos (m_ν > 1 keV) and that their decays can serve as a heating source for the hot gas in galaxy clusters, we study how the observational constraints on cooling flow limit the masses of these sterile neutrinos. We predict a relation among the luminosity, the total mass, and the redshift of a cluster, and we compare this relation with data from 12 clusters to obtain an estimate of the decay rate of sterile neutrinos. Copyright © 2007 The American Astronomical Society.