Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: 2dF-AAOmega spectroscopy of massive stars in the Magellanic Clouds: The
  north-eastern region of the Large Magellanic Cloud   We present spectral classifications from optical spectroscopy of 263 massive
stars in the north-eastern region of the Large Magellanic Cloud. The observed
two-degree field includes the massive 30 Doradus star-forming region, the
environs of SN1987A, and a number of star-forming complexes to the south of 30
Dor. These are the first classifications for the majority (203) of the stars
and include eleven double-lined spectroscopic binaries. The sample also
includes the first examples of early OC-type spectra (AAOmega 30 Dor 248 and
280), distinguished by the weakness of their nitrogen spectra and by C IV 4658
emission. We propose that these stars have relatively unprocessed CNO
abundances compared to morphologically normal O-type stars, indicative of an
earlier evolutionary phase. From analysis of observations obtained on two
consecutive nights, we present radial-velocity estimates for 233 stars, finding
one apparent single-lined binary and nine (>3sigma) outliers compared to the
systemic velocity; the latter objects could be runaway stars or large-amplitude
binary systems and further spectroscopy is required to investigate their
nature.

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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
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The categories of this paper are: econ
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: gr-qc
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The categories of this paper are: comp-gas
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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: q-fin
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-bio
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The categories of this paper are: funct-an
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The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an