Spectroscopic Follow-up of the CFBDS T DwarfCandidates

摘要

The Canada-France Brown Dwarfs Survey (CFBDS) will be covering approximately 900 sq.deg. in the i and z bands using MegaCam at CFHT to search for cool brown dwarfs and determineL and T dwarfs density functions. Here we present spectra obtained at Gemini of candidates drawnfrom the first half of the survey, mostly T-type brown dwarfs. About 20 targets are new discoveriesand several are of special interest, being either ultra cool, very old or sub metallic. We also presentfollow-up near-infrared photometry and proper motion measurements for about a dozen dwarfs.