Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The missing link: Merging neutron stars naturally produce jet-like
  structures and can power short Gamma-Ray Bursts   Short Gamma-Ray Bursts (SGRBs) are among the most luminous explosions in the
universe, releasing in less than one second the energy emitted by our Galaxy
over one year. Despite decades of observations, the nature of their
"central-engine" remains unknown. Considering a binary of magnetized neutron
stars and solving Einstein equations, we show that their merger results in a
rapidly spinning black hole surrounded by a hot and highly magnetized torus.
Lasting over 35 ms and much longer than previous simulations, our study reveals
that magnetohydrodynamical instabilities amplify an initially turbulent
magnetic field of ~ 10^{12} G to produce an ordered poloidal field of ~ 10^{15}
G along the black-hole spin-axis, within a half-opening angle of ~ 30 deg,
which may naturally launch a relativistic jet. The broad consistency of our
ab-initio calculations with SGRB observations shows that the merger of
magnetized neutron stars can provide the basic physical conditions for the
central-engine of SGRBs.

37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat