  Recent Strong lensing data and rotation curves of dwarf galaxies indicate
that many galactic clusters may have a soft core instead of a central cusp in
their density distribution. This result challenges the standard CDM (Cold Dark
Matter) theory prediction based on N-body simulations. We find that the
observed density profile is consistent with that of a spherical gas of
degenerate fermions such as neutrinos in hydrostatic equilibrium. Also, we
compare two different models of the dark matter halo and their predictions for
the hot gas profile.

Astrophysics