Blue not brown: UKIRT Infrared Deep Sky Survey T dwarfs with suppressed K-band flux

Abstract

We have used blue near-infrared colours to select a group of 12 spectroscopically confirmed United Kingdom InfraRed Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) T dwarfs later than T4. From amongst these, we identify the first two kinematic halo T-