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White dwarfs in the UKIRT Infrared Deep Sky Survey Large Area Survey: the substellar companion fraction


Steele, PR and Burleigh, MR and Dobbie, PD and Jameson, RF and Barstow, MA and Satterthwaite, RP, White dwarfs in the UKIRT Infrared Deep Sky Survey Large Area Survey: the substellar companion fraction, Monthly Notices of the Royal Astronomical Society, 416, (4) pp. 2768-2791. ISSN 0035-8711 (2011) [Refereed Article]

Copyright Statement

Copyright 2011 The Authors. Monthly Notices of the Royal Astronomical Society  2011 RAS

DOI: doi:10.1111/j.1365-2966.2011.19225.x


We present a near-infrared photometric search for unresolved substellar companions and debris discs around white dwarfs in the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey. We cross-correlate the Sloan Digital Sky Survey (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 disc. Where present, we have estimated the approximate spectral type of any putative companion, or an upper limit on the temperature of a debris disc. In total we identify 1416 new candidate white dwarf + very low mass stellar systems, 911 candidate white dwarf + brown dwarf systems, and three candidate white dwarf + debris discs. We place lower limits on the unresolved (<2 arcsec) 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 WD+dL ≥ 0.4 0.3 per cent, WD+dT ≥ 0.2 per cent and WD+BD ≥ 0.5 0.3 per cent.

Item Details

Item Type:Refereed Article
Keywords:brown dwarfs; stars: low-mass; white dwarfs; infrared: stars
Research Division:Physical Sciences
Research Group:Astronomical and Space Sciences
Research Field:Stellar Astronomy and Planetary Systems
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
ID Code:80996
Year Published:2011
Web of Science® Times Cited:41
Deposited By:Mathematics and Physics
Deposited On:2012-11-20
Last Modified:2013-06-27

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