Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: MeV Gamma Rays from Fission: A Distinct Signature of Actinide Production
  in Neutron Star Mergers   Neutron star mergers (NSMs) are the first verified sites of rapid neutron
capture (r-process) nucleosynthesis, and could emit gamma rays from the
radioactive isotopes synthesized in the neutron-rich ejecta. These MeV gamma
rays may provide a unique and direct probe of the NSM environment as well as
insight into the nature of the r process, just as observed gammas from the 56Ni
radioactive decay chain provide a window into supernova nucleosynthesis. In
this work, we include the photons from fission processes for the first time in
estimates of the MeV gamma-ray signal expected from an NSM event. We consider
NSM ejecta compositions with a range of neutron richness and find a dramatic
difference in the predicted signal depending on whether or not fissioning
nuclei are produced. The difference is most striking at photon energies above
~3.5 MeV and at a relatively late time, several days after the merger event,
when the ejecta is optically thin. We estimate that a Galactic NSM could be
detectable by a next generation gamma-ray detector such as AMEGO in the MeV
range, up to ~10^4 days after the merger, if fissioning nuclei are robustly
produced in the event.

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The categories of this paper are: cs
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The categories of this paper are: alg-geom
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The categories of this paper are: bayes-an
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The categories of this paper are: ao-sci
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The categories of this paper are: q-fin
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The categories of this paper are: chem-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: hep-lat
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The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
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The categories of this paper are: mtrl-th
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The categories of this paper are: plasm-ph