Near-Infrared Proper Motion Surveys

Abstract

I present the development of two near infrared proper motion pipelines for high resolution near infrared data from UKIDSS and the VISTA VVV survey. The UKIDSS pipeline is capable of accuracies of order 5 − 10 mas yr−1 for bright sources with the largest epoch baselines (∼ 8 years). The VVV pipeline reaches 1 − 2 mas yr−1 proper motion precision at the bright end and parallax measurements at ∼ 1 mas precision. It will be possible to improve upon the VVV astrometric precision due to increases in data volume and further pipeline development. I have used the proper motion pipelines to generate three near infrared proper motion catalogues of the UKIDSS LAS and GPS and the VVV survey. The LAS proper motion catalogue covers 1500 deg2 at high Galactic latitudes and contains approximately 15 million sources with two J band epochs. The GPS proper motion catalogue covers 1500 deg2 of the northern Galactic plane and contains approximately 400 million sources with two K band epochs. The VVV proper motion catalogue covers 560 deg2 of the Galactic bulge and disc and contains approximately 200 million sources with between 50 and 150 Ks band epochs. I have also produced a preliminary 5σ parallax catalogue containing 3403 VVV sources. The LAS and GPS proper motion catalogues have been used by myself and other authors to identify and study many new examples of high proper motion stars, brown dwarfs, ul-tracool dwarf benchmark candidates, cool white dwarfs, substellar subdwarfs and nearby sources within < 25 pc. These catalogues remain far from fully exploited and will be a useful resource for future research by the astronomical community. Exploitation of the VVV proper motion catalogue is still in its infancy, yet it has already generated large numbers of new high proper motion sources. These include new brown dwarf candi-dates, important benchmark objects, and nearby sources which have previously avoided detection. Parallax results from the VVV pipeline will be useful to improve low mass star/ultracool dwarf luminosity functions, significantly increasing the numbers of brown dwarfs with known parallaxes and illustrates how general purpose multi-epoch wide area surveys can generate parallaxes. Finally, I discuss the long term usefulness of such catalogues in the Gaia era and how they might be exploited in the future.