Galactic Constraints on Fermionic Dark Matter

Abstract

In order to explain Galactic structures, a self-gravitating system composed of massive fermions in spherical symmetry is considered. The finite mass distribution of such a component is obtained after solving the Einstein equation for a thermal and semi-degenerate fermionic gas, described by a perfect fluid in hydrostatic equilibrium and exposed to cutoff effects (e.g. evaporation). Within this more general approach a family of density profiles arises, which explains dark matter halo constraints of the Galaxy and provides at the same time an alternative to the central black hole scenario in Sgr A*. This analysis narrows the allowed particle mass to mc² = 48−345 keV.