Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Neutrino pair annihilation above merger remnants: implications of a
  long-lived massive neutron star   Binary neutron star mergers are plausible progenitor candidates for short
gamma-ray bursts (GRBs); however, a detailed explanation of their central
engine is still lacking. The annihilation of neutrino pairs has been proposed
as one of the possible powering mechanisms. We present calculations of the
energy and momentum deposition operated by neutrino pair annihilation above
merger remnants. Starting from the results of a detailed, three-dimensional
simulation of the aftermath of a binary neutron star merger, we compute the
deposition rates over a time scale comparable to the life time of the disk ($t
\approx 0.4$ s), assuming a long-lived massive neutron star (MNS). We model
neutrino emission using a spectral leakage scheme and compute the neutrino
annihilation rates using a ray-tracing algorithm. We find that the presence of
the MNS increases the energy deposition rate by a factor $\sim 2$, mainly due
to the annihilation of radiation coming from the MNS with radiation coming from
the disk. We compute the impact of relativistic effects and discover that,
despite they can significantly change the local rate intensity, the
volume-integrated results are only marginally decreased. The cumulative
deposited energy, extrapolated to 1 sec, is $\approx 2.2 \times 10^{49} \, {\rm
erg}$. A comparison with the inferred short GRB energetics reveals that in most
cases this energy is not large enough, even assuming small jet opening angles
and a long-lived MNS. Significantly more intense neutrino luminosities (a
factor ~5-10 larger) are required to explain most of the observed short GRB. We
conclude that it is unlikely that neutrino pair annihilation can explain the
central engine of short GRBs alone.

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The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat