Bibcode
Lodieu, N.; Dobbie, P. D.; Deacon, N. R.; Venemans, B. P.; Durant, M.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 395, Issue 3, pp. 1631-1639.
Advertised on:
5
2009
Citations
10
Refereed citations
8
Description
We present the discovery of two brown dwarfs in the UK infrared
Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) Deep Extragalactic
Survey (DXS) Data Release 2 (DR2). Both objects were selected
photometrically from 6deg2 in DXS for their blue J - K colour
and the lack of optical counterparts in the Sloan Digital Sky Survey
(SDSS) Stripe 82. Additional optical photometry provided by the
Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) corroborated the
possible substellarity of these candidates. Subsequent methane imaging
of UDXS J221611.51+003308.1 and UDXS J221903.10+002418.2 has confirmed
them as T7 +/- 1 and T6 +/- 1 dwarfs at photometric distances of 81
(52-118 pc) and 60 (44-87 pc; 2σ confidence level). A similar
search in the DR2 of the Ultra-Deep Survey over a smaller area
(0.77deg2) and shallower depth did not return any late-T
dwarf candidate. The numbers of late-T dwarfs in our study are broadly
in line with a declining mass function when considering the current area
and depth of the DXS and UDS. These brown dwarfs are the first
discovered in the Visible Imaging Multi-Object Spectrograph (VIMOS) 4
field and among the few T dwarfs found in pencil-beam surveys. They are
valuable to investigate the scaleheight of T dwarfs.
Based on observations made with the United Kingdom Infrared Telescope,
the Canada-France-Hawaii Telescope Legacy Survey and the Gemini
Observatory.
E-mail: nlodieu [at] iac.es (nlodieu[at]iac[dot]es)