Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical Observations of the Binary Millisecond Pulsars J2145-0750 and
  J0034-0534   We report on optical observations of the low-mass binary millisecond pulsar
systems J0034-0534 and J2145-0750. A faint (I=23.5) object was found to be
coincident with the timing position of PSR J2145-0750. While a galaxy or
distant main-sequence star cannot be ruled out, its magnitude is consistent
with an ancient white dwarf, as expected from evolutionary models. For PSR
J0034-0534 no objects were detected to a limiting magnitude of R=25.0,
suggesting that the white dwarf in this system is cold. Using white dwarf
cooling models, the limit on the magnitude of the PSR J0034-0534 companion
suggests that at birth the pulsar in this system may have rotated with a period
as short as 0.6 ms. These observations provide further evidence that the
magnetic fields of millisecond pulsars do not decay on time scales shorter than
1 Gyr.

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The categories of this paper are: alg-geom
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The categories of this paper are: cs
0
The categories of this paper are: hep-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
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The categories of this paper are: funct-an
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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-th
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The categories of this paper are: math
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The categories of this paper are: nucl-ex
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The categories of this paper are: adap-org
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: eess