Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: GRBs from Weakly-Magnetized, Slowly-Rotating Stars in Binaries   The spin of a number of black holes (BHs) in X-ray binaries (XBs) has been
predicted (and, in at least three cases, confirmed by observations) by using a
binary stellar evolution model with Case-C mass transfer . The rotational
energy of such BHs is sufficient to power up (long) gamma-ray bursts and
hypernovae (GRBs/HNe) and still leave a Kerr BH behind. However, strong
magnetic fields (B fields) and/or dynamo effects in the interior of a
BH-progenitor star may be capable of rapidly depleting the angular momentum
from the stellar core, hence, preventing the formation of a collapsar. Thus,
even if binaries can produce Kerr BHs, most of their rotation is acquired from
accreting the stellar mantle, with a long delay between the formation of the BH
and its spin up. Hence, not being good sources of GRBs.
  We study the necessary conditions to produce GRBs by the progenitors of such
BHs. Tidal-synchronization and Alfv\'en timescales are compared for B fields of
different intensities threading trough He stars. We search for a B-field range
which allows tidal spin up all the way into stellar core but prevents its slow
down during differential rotation phases. Energetics for producing a strong B
field during core collapse, which allows for GRB central engines, are also
estimated. An observationally-reasonable choice of parameters is found.

12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
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The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
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The categories of this paper are: econ
0
The categories of this paper are: hep-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: eess