Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Many faces of accretion in gamma ray bursts   Accretion powers relativistic jets in GRBs, similarly to other jet sources.
Black holes that are at heart of long GRBs, are formed as the end product of
stellar evolution. At birth, some of the black holes must be very rapidly
spinning, to be able to power the GRBS. In some cases, the black holes may be
born without formation of a disk/jet engine, and then the star will collapse
without an electromagnetic transient. In this proceeding, we discuss the
conditions for launching variable jets from the magnetized disk in an arrested
state. We also discuss properties of collapsing massive stars as progenitors of
GRBs, and the conditions which must be satisfied for the star in order for the
collapsar to produce a bright gamma-ray transient. We find that the black hole
rotation is further affected by self-gravity of the collapsing matter. Finally,
we comment on the properties of the accretion disk under extreme conditions of
nuclear densities and temperatures, while it can contribute to the kilonova
accompanying short GRBs.

9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th