Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: H{\alpha} imaging for BeXRBs in the Small Magellanic Cloud   The Small Magellanic Cloud (SMC) hosts a large number of high-mass X-ray
binaries, and in particular of Be/X-ray Binaries (BeXRBs; neutron stars
orbiting OBe-type stars), offering a unique laboratory to address the effect of
metalicity. One key property of their optical companion is H{\alpha} in
emission, which makes them bright sources when observed through a narrow-band
H{\alpha} filter. We performed a survey of the SMC Bar and Wing regions using
wide-field cameras (WFI@MPG/ESO and MOSAIC@CTIO/Blanco) in order to identify
the counterparts of the sources detected in our XMM-Newton survey of the same
area. We obtained broad-band R and narrow-band H{\alpha} photometry, and
identified ~10000 H{\alpha} emission sources down to a sensitivity limit of
18.7 mag (equivalent to ~B8 type Main Sequence stars). We find the fraction of
OBe/OB stars to be 13% down to this limit, and by investigating this fraction
as a function of the brightness of the stars we deduce that H{\alpha} excess
peaks at the O9-B2 spectral range. Using the most up-to-date numbers of SMC
BeXRBs we find their fraction over their parent population to be ~0.002-0.025
BeXRBs/OBe, a direct measurement of their formation rate.

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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ph
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The categories of this paper are: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: nucl-ex
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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: plasm-ph
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The categories of this paper are: supr-con
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The categories of this paper are: q-fin
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The categories of this paper are: physics
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The categories of this paper are: q-bio
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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom