## Degenerate sterile neutrino dark matter in the cores of galaxies.(English)Zbl 1101.85316

Summary: 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 keV and for distances less than a few parsec from the center of our galaxy.
Methods. 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 $$\sim3.5\times 10^6$$ $$M_{}$$ and a supermassive black hole of $$\sim3.5\times 10^9$$ $$M_{}$$ at a redshift of 6.41 in SDSS quasars, we require a degenerate core of mass between $$3.5\times 10^3$$ $$M_{}$$ and $$3.5.\times 10^6$$ $$M_{}$$. This constrains the mass of the dark matter particle between and $$0.6$$ keV and 82 keV. The lower limit on the dark matter mass is improved to 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.

### MSC:

 85A40 Astrophysical cosmology
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