Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Black Hole inside Dark Matter and the Rotation Curves of Galaxies   In this article we find a four-dimensional metric for a large black hole
immersed in dark matter. Specifically, we look for and find a static
spherically symmetric black hole solution to the Einstein equations which
gives, in the Newtonian limit, the rotation curves of galaxies, including the
flat region and the Baryonic Tully-Fisher relation, and which has a regular
horizon. We obtain as well the energy-momentum tensor of the dark matter
sourcing this space-time and it turns, in special, to satisfy the four energy
conditions (dominant, weak, null, and strong) everywhere outside the horizon.
This black-hole-dark-matter system represents a successful simplified model for
galaxies, opens a new area for exploring the relativistic regime of dark
matter, and shows that the theory of General Relativity together with dark
matter can account for the rotation curves of galaxies.

1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin