Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hyperaccreting Disks around Neutrons Stars and Magnetars for GRBs:
  Neutrino Annihilation and Strong Magnetic Fields   Hyperaccreting disks around neutron stars or magnetars cooled via neutrino
emission can be the potential central engine of GRBs. The neutron-star disk can
cool more efficiently, produce much higher neutrino luminosity and neutrino
annihilation luminosity than its black hole counterpart with the same accretion
rate. The neutron star surface boundary layer could increase the annihilation
luminosity as well. An ultra relativistic jet via neutrino annihilation can be
produced along the stellar poles. Moreover, we investigate the effects of
strong fields on the disks around magnetars. In general, stronger fields give
higher disk densities, pressures, temperatures and neutrino luminosity; the
neutrino annihilation mechanism and the magnetically-driven pulsar wind which
extracts the stellar rotational energy can work together to generate and feed
an even stronger ultra-relativistic jet along the stellar magnetic poles.

19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs