Do non-relativistic neutrinos constitute the dark matter?Th. M. Nieuwenhuizen
Institute for Theoretical Physics, University of Amsterdam - Valckenierstraat 65, 1018 XE Amsterdam, The Netherlands, EU
received on 13 May 2009; accepted in final form by R. A. Treumann on 18 May 2009; published June 2009
published online 29 May 2009
The dark matter of the Abell 1689 Galaxy Cluster is modeled by thermal, non-relativistic gravitating fermions and its galaxies and X-ray gas by isothermal distributions. A fit yields a mass of eV. A dark-matter fraction occurs for = 12 degrees of freedom, i.e., for 3 families of left- plus right-handed neutrinos with masses . Given a temperature of 0.045 K and a de Broglie length of 0.20 mm, they establish a quantum structure of several million light years across, the largest known in the Universe. The virial -particle temperature of 9.91.1 keV/kB coincides with the average one of X-rays. The results are compatible with neutrino genesis, nucleosynthesis and free streaming. The neutrinos condense on the cluster at redshift z~28, thereby causing reionization of the intracluster gas without assistance of heavy stars. The baryons are poor tracers of the dark-matter density.
95.35.+d - Dark matter (stellar, interstellar, galactic, and cosmological).
98.65.-r - Galaxy groups, clusters, and superclusters; large scale structure of the Universe.
14.60.St - Non-standard-model neutrinos, right-handed neutrinos, etc..
© EPLA 2009