Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The effects of r-process heating on fall-back accretion in compact
  object mergers   We explore the effects of r-process nucleosynthesis on fall-back accretion in
neutron star(NS)-NS and black hole-NS mergers, and the resulting implications
for short-duration gamma-ray bursts (GRBs). Though dynamically important, the
energy released during the r-process is not yet taken into account in merger
simulations. We use a nuclear reaction network to calculate the heating (due to
beta-decays and nuclear fission) experienced by material on the
marginally-bound orbits nominally responsible for late-time fall-back. Since
matter with longer orbital periods t_orb experiences lower densities, for
longer periods of time, the total r-process heating rises rapidly with t_orb,
such that material with t_orb > 1 seconds can become completely unbound. Thus,
r-process heating fundamentally changes the canonical prediction of an
uninterrupted power-law decline in the fall-back rate dM/dt at late times. When
the timescale for r-process to complete is > 1 second, the heating produces a
complete cut-off in fall-back accretion after ~ 1 second; if robust, this would
imply that fall-back accretion cannot explain the late-time X-ray flaring
observed following some short GRBs. However, for a narrow, but physically
plausible, range of parameters, fall-back accretion can resume after ~ 10 s,
despite having been strongly suppressed for ~ 1-10 s after the merger. This
suggests the intriguing possibility that the gap observed between the prompt
and extended emission in short GRBs is a manifestation of r-process heating.

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The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin
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The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: solv-int
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The categories of this paper are: nlin
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The categories of this paper are: eess
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: econ
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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: funct-an