Neutrino dark matter in clusters of galaxies

We present a model calculation for the radial matter density and mass distr ibution in two clusters of galaxies (Coma and A119) including cold dark mat ter, massive though light (similar or equal to2 eV) neutrino dark matter an d collisional intra-cluster gas which emits x-ray radiation. The calculatio n uses an extension of the Lynden-Bell statistics to the choice of constant masses instead of constant volume. This allows proper inclusion of mixture s of particles of various masses in the gravitational interaction. When it is applied to the matter in the galaxy cluster the radial ROSAT x-ray lumin osity profiles can be nicely accounted for. The result is that the statisti cs identifies the neutrino dark matter in the cluster centre as being degen erate in the sense of Lynden-Bell's spatial degeneracy. This implies that i t is distributed in a way different from the classical assumption. The best fits are obtained for the similar or equal to2 eV neutrinos. The fraction of these and their spatial distribution are of interest for understanding c luster dynamics and may have cosmological implications.