Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Astrophysical Limits on Massive Dark Matter   Annihilations of weakly interacting dark matter particles provide an
important signature for the possibility of indirect detection of dark matter in
galaxy halos. These self-annihilations can be greatly enhanced in the vicinity
of a massive black hole. We show that the massive black hole present at the
centre of our galaxy accretes dark matter particles, creating a region of very
high particle density. Consequently the annihilation rate is considerably
increased, with a large number of $e^+e^-$ pairs being produced either directly
or by successive decays of mesons. We evaluate the synchrotron emission (and
self-absorption) associated with the propagation of these particles through the
galactic magnetic field, and are able to constrain the allowed values of masses
and cross sections of dark matter particles.

30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio