Do non-relativistic neutrinos constitute the dark matter?

Understand

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 $h_{70}^{1/2}(12/{\overline g})^{1/4}$1.445 $(30)$ eV.
• A dark matter fraction $\Omega_\nu=h_{70}^{-3/2}0.1893$ $(39)$ occurs for ${\overline g}=12$ degrees of freedom, i.
• e., for 3 families of left plus right handed neutrinos with masses $\approx 2^{3/4}G_F^{1/2}m_e^2$.