The UKIDSS–2MASS proper motion survey – I. Ultracool dwarfs from UKIDSS DR4 |
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Authors: | N R Deacon N C Hambly R R King M J McCaughrean |
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Institution: | Department of Astrophysics, Faculty of Science, Radboud University Nijmegen, PO Box 9010, 6500 GL Nijmegen, the Netherlands;SUPA, Institute for Astronomy, School of Physics, University of Edinburgh, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ;Astrophysics Group, School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL |
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Abstract: | The UK Infrared Telescope Infrared Deep Sky Survey (UKIDSS) is the first of a new generation of infrared surveys. Here, we combine the data from two UKIDSS components, the Large Area Survey (LAS) and the Galactic Cluster Survey (GCS), with Two-Micron All-Sky Survey (2MASS) data to produce an infrared proper motion survey for low-mass stars and brown dwarfs. In total, we detect 267 low-mass stars and brown dwarfs with significant proper motions. We recover all 10 known single L dwarfs and the one known T dwarf above the 2MASS detection limit in our LAS survey area and identify eight additional new candidate L dwarfs. We also find one new candidate L dwarf in our GCS sample. Our sample also contains objects from 11 potential common proper motion binaries. Finally, we test our proper motions and find that while the LAS objects have proper motions consistent with absolute proper motions, the GCS stars may have proper motions which are significantly underestimated. This is possibly due to the bulk motion of some of the local astrometric reference stars used in the proper motion determination. |
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Keywords: | astronomical data bases: miscellaneous surveys astrometry stars: low-mass brown dwarfs stars: luminosity function mass function infrared: stars |
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