Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dispersion and Rotation Measures from the Ejecta of Compact Binary
  Mergers: Clue to the Progenitors of Fast Radio Bursts   Since the discovery of FRB 200428 associated with the Galactic SGR 1935+2154,
magnetars are considered to power fast radio bursts (FRBs). It is widely
believed that magnetars could form by core-collapse (CC) explosions and compact
binary mergers, such as binary neutron star (BNS), binary white dwarfs (BWD),
and neutron star-white dwarf (NSWD) mergers. Therefore, it is important to
distinguish the various progenitors. The expansion of the merger ejecta
produces a time-evolving dispersion measure (DM) and rotation measure (RM) that
can probe the local environments of FRBs. In this paper, we derive the scaling
laws for the DM and RM from ejecta with different dynamical structures (the
mass and energy distribution) in the uniform ambient medium (merger scenario)
and wind environment (CC scenario). We find that the DM and RM will increase in
the early phase, while DM will continue to grow slowly but RM will decrease in
the later phase in the merger scenario. We fit the DM and RM evolution of FRB
121102 simultaneously for the first time in the BNS merger scenario, and find
the source age is $ \sim9-10 $ yr when it was first detected in 2012, and the
ambient medium density is $ \sim 2.5-3.1 $ cm$ ^{-3} $. The large offsets of
some FRBs are consistent with BNS/NSWD channel. The population synthesis method
is used to estimate the rate of compact binary mergers. The rate of BWD mergers
is close to the observed FRB rate. Therefore, the progenitors of FRBs may not
be unique.

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The categories of this paper are: stat
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The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: q-alg
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The categories of this paper are: math
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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
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The categories of this paper are: gr-qc
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The categories of this paper are: funct-an