Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: PSR J1618-3921: a recycled pulsar in an eccentric orbit   PSR~J1618$-$3921 is an $11.99$-ms pulsar in a $22.7$-d orbit around a likely
low-mass He white dwarf companion, discovered in a survey of the intermediate
Galactic latitudes at 1400 MHz conducted with the Parkes radio telescope in the
late 1990s. Although PSR~J1618$-$3921 was discovered more than 15 years ago,
only limited information has been published about this pulsar which has a
surprisingly large orbital eccentricity ($e \simeq 0.027$), considering its
high spin frequency and likely small companion mass. The focus of this work is
a precise measurement of the spin, astrometric and orbital characteristics of
PSR J1618$-$3921. This was done with timing observations made at the Nan\c{c}ay
Radio Telescope, from 2009 to 2017. We analyzed the timing data recorded at the
Nan\c{c}ay Radio Telescope over several years to characterize the properties of
PSR~J1618$-$3921. A rotation ephemeris for this pulsar was obtained by
analyzing the times of arrival of the radio pulses at the telescope. We confirm
the unusual eccentricity of PSR~J1618$-$3921 and discuss several hypotheses
regarding its formation, in the context of other discoveries of recycled
pulsars in eccentric orbits.

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The categories of this paper are: plasm-ph
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The categories of this paper are: solv-int
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The categories of this paper are: gr-qc
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The categories of this paper are: quant-ph
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The categories of this paper are: econ
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The categories of this paper are: hep-th
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The categories of this paper are: q-fin
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The categories of this paper are: math
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The categories of this paper are: math-ph
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The categories of this paper are: eess
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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: hep-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg