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A cross-match of 2MASS and SDSS: newly found L and T dwarfs and an estimate of the space density of T dwarfs

Metchev, Stanimir A. and Kirkpatrick, J. Davy and Berriman, G. Bruce and Looper, Dagny (2008) A cross-match of 2MASS and SDSS: newly found L and T dwarfs and an estimate of the space density of T dwarfs. Astrophysical Journal, 676 (2). pp. 1281-1306. ISSN 0004-637X.

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We report new L and T dwarfs found in a cross-match of the SDSS Data Release 1 and 2MASS. Our simultaneous search of the two databases effectively allows us to relax the criteria for object detection in either survey and to explore the combined databases to a greater completeness level. We find two new T dwarfs in addition to the 13 already known in the SDSS DR1 footprint. We also identify 22 new candidate and bona fide L dwarfs, including a new young L2 dwarf and a peculiar potentially metal-poor L2 dwarf with unusually blue near-IR colors. These discoveries underscore the utility of simultaneous database cross-correlation in searching for rare objects. Our cross-match completes the census of T dwarfs within the joint SDSS and 2MASS flux limits to the ≈97% level. Hence, we are able to accurately infer the space density of T dwarfs. We employ Monte Carlo tools to simulate the observed population of SDSS DR1 T dwarfs with 2MASS counterparts and find that the space density of T0 - T8 dwarf systems is 0.0070^(+0.0032)_ (-0.0030) pc^-3 (95% confidence interval), i.e., about one per 140 pc^3. Compared to predictions for the T dwarf space density that depend on various assumptions for the substellar mass function, this result is most consistent with models that assume a flat substellar mass function dN/dM ∝ M^0.0. No >T8 dwarfs were discovered in the present cross-match, although less than one was expected in the limited area (2099 deg^2) of SDSS DR1.

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Metchev, Stanimir A.0000-0003-3050-8203
Kirkpatrick, J. Davy0000-0003-4269-260X
Berriman, G. Bruce0000-0001-8388-534X
Additional Information:© 2008 American Astronomical Society. Received 2007 February 24; accepted 2007 October 18. The SDSS DR1/2MASS database cross-match was funded as a demonstration project by the NSF National Partnership for Advanced Computational Infrastructure and by the National Virtual Observatory, sponsored by the NSF.We thank Serge Monkewitz for developing the cross-match engine.We thank Gillian Knapp for assistance with SDSS and Katelyn Allers for providing us with her IRTF SpeX spectrum of G196-3B. We acknowledge Tiffany Meshkat for help with the acquisition and reduction of the Lick PFCam data. This research has made use of the NASA/IPAC Infrared Science Archive (IRSA), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This research has also benefitted from the M, L, and T dwarf compendium housed at and maintained by Chris Gelino, Davy Kirkpatrick, and Adam Burgasser. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. The Sloan Digital Sky Survey is managed by ARC for the Participating Institutions: the University of Chicago, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Korean Scientist Group, Los Alamos National Laboratory, the Max Planck Institute for Astronomy, the Max Planck Institute for Astrophysics, New Mexico State University, the University of Pittsburgh, the University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington. Funding for SDSS has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, NASA, the NSF, the US Department of Energy, the Japanese Monbukagakusho, and the Max Planck Society. Support for S. A. M. was provided by NASA through the Spitzer Fellowship Program, under award 1273192. Facilities: Keck:I, PO:1.5m, UH:2.2m, IRTF, Shane, Spitzer
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Alfred P. Sloan FoundationUNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
Japanese MonbukagakushoUNSPECIFIED
Max Planck SocietyUNSPECIFIED
University of ChicagoUNSPECIFIED
Institute for Advanced StudyUNSPECIFIED
Japan Participation GroupUNSPECIFIED
Johns Hopkins UniversityUNSPECIFIED
Korean Scientist GroupUNSPECIFIED
Los Alamos National LaboratoryUNSPECIFIED
Max Planck Institute for AstronomyUNSPECIFIED
Max Planck Institute for AstrophysicsUNSPECIFIED
New Mexico State UniversityUNSPECIFIED
University of PittsburghUNSPECIFIED
University of PortsmouthUNSPECIFIED
Princeton UniversityUNSPECIFIED
United States Naval ObservatoryUNSPECIFIED
University of WashingtonUNSPECIFIED
Subject Keywords:stars: individual (2MASS J00521232+0012172, 2MASS J01040750–0053283, 2MASS J01262109+1428057, 2MASS J09175418+6028065, 2MASS J12144089+6316434, 2MASS J13243553+6358281, 2MASS J15461461+4932114); stars: low-mass, brown dwarfs; surveys
Issue or Number:2
Record Number:CaltechAUTHORS:METapj08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13810
Deposited By: Jason Perez
Deposited On:04 May 2009 19:10
Last Modified:28 Oct 2019 21:36

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