UKIDSS

Speaker: David Pinfield

The UK Infrared Deep Sky Survey (UKIDSS) is the next generation near-infrared sky survey, and successor to 2MASS. It consists of 5 separate sub-surveys, each using a combination of the ZYJHK pass bands. The full project goal is to survey 7500 square degrees of the northern and equatorial sky. The survey instrument is WFCAM on the UK Infrared Telescope (UKIRT) in Hawaii, which has four 2048x2048 arrays, a pixel scale of 0.4 arcsec, and covers 0.21 sq. degs at once.

In this talk I will focus mainly on the UKIDSS Large Area Survey (LAS), which plans to cover 4000 sq degs of Sloan sky to depths approximately three magnitudes deeper than 2MASS. In the much larger survey volume we expect to probe lower Teff extremes, lower masses, and older low-mass stars and brown dwarfs, as well as finding much larger numbers of previously known populations. These larger samples should yield a cull of particularly interesting low-mass objects that could shed new light on our understanding of cool star and brown dwarf atmospheres.

Since UKIDSS began in May 2005 there have been two data releases, and there are third and fourth releases due early next year. These will take LAS coverage up to about 1000 sq degs. I will summarise some early discoveries from the first two releases, and present predictions of interesting populations of "benchmark objects" (ie cool stars and brown dwarfs whose properties are, by some means, well constrained) that could be identified in the future. These benchmark objects should allow us to improve our understanding of cool star and brown dwarf atmospheres, and help place constraints on the mass-age distribution of the low-mass disk population.