Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: White dwarfs in the UKIDSS Large Area Survey: The Substellar Companion
  Fraction   We present a near-infrared photometric search for unresolved substellar
companions and debris disks around white dwarfs in the UKIRT Infrared Deep Sky
Survey Large Area Survey. We cross-correlate the SDSS DR4 and McCook & Sion
catalogues of white dwarfs with the UKIDSS DR8 producing 3109 and 163 unique
matches respectively. Cooling models are fitted to the optical photometry of a
subsample of DA white dwarfs and extended to the near-infrared. A comparison is
then made with the observed photometry to identify those stars with a
near-infrared excess consistent with the presence of a cool companion or debris
disk. Where present, we have estimated the approximate spectral type of any
putative companion, or an upper limit on the temperature of a debris disk. In
total we identify 14-16 new candidate white dwarf + very low mass stellar
systems, 9-11 candidate white dwarf + brown dwarf systems, and 3 candidate
white dwarf + debris disks. We place lower limits on the unresolved (<2")
companions to all DA white dwarfs and thus assess the sensitivity of UKIDSS to
such objects. We use this result to estimate unresolved binary fractions of
f(WD+dL)>0.4+/-0.3%, f(WD+dT)>0.2% and f(WD+BD)>0.5+/-0.3%.

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The categories of this paper are: acc-phys
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The categories of this paper are: quant-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: cond-mat
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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: math
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The categories of this paper are: dg-ga
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The categories of this paper are: cmp-lg
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
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The categories of this paper are: cs