  We study the distribution of fermionic dark matter at the center of galaxies
using NFW, Moore and isothermal density profiles and show that dark matter
becomes degenerate for particle masses of a few {\rm keV} and for distances
less than a few parsec from the center of our galaxy. A compact degenerate core
forms after galaxy merging and boosts the growth of supermassive black holes at
the center of galaxies. To explain the galactic center black hole of mass of
$\sim 3.5 \times 10^{6}M_{\odot}$ and a supermassive black hole of $\sim 3
\times 10^{9}M_{\odot}$ at a redshift of 6.41 in SDSS quasars, we require a
degenerate core of mass between $3 \times 10^{3} M_{\odot}$ and $3.5 \times
10^{6}M_{\odot}$. This constrains the mass of the dark matter particle between
$0.6 {\rm keV}$ and $82 {\rm keV}$. The lower limit on the dark matter mass is
improved to {\rm 7 keV} if exact solutions of Poisson's equation are used in
the isothermal power law case. We argue that the constrained particle could be
the long sought dark matter of the Universe that is interpreted here as a
sterile neutrino.
