MOND and neutrinos: The dark matter density–temperature diagram for X-ray clusters

Neutrinos have been postulated as a major contributor to the mass of galaxy clusters, particularly in the framework of Modified Newtonian Dynamics (MOND). Recent X-ray and gravitational lensing analyses have claimed that the picture is difficult to maintain since too heavy a neutrino would be necessary. We explicitly reviewed the main instrument on which most of these conclusions hinge, the dark matter density–temperature (DT) diagram, and analyze it for an X-ray flux limited sample of nearby clusters. We analyzed the DT-diagram from a Newtonian and a MONDian perspectives. Differently from recent lensing analyses, our study of the DT-diagram for X-ray clusters has not ruled out neutrinos of mν≲2eV as a major contributor to the cluster mass.