Details

Autor(en) / Beteiligte

• Metchev, Stanimir A
• Kirkpatrick, J. Davy
• Berriman, G. Bruce
• Looper, Dagny

Titel

A Cross-Match of 2MASS and SDSS: Newly Found L and T Dwarfs and an Estimate of the Space Density of T Dwarfs

Ist Teil von

• The Astrophysical journal, 2008-04, Vol.676 (2), p.1281-1306

Ort / Verlag

Chicago, IL: IOP Publishing

Erscheinungsjahr

2008

Link zum Volltext

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• 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 [sim]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 [image] pc super(-3) (95% confidence interval), i.e., about one per 140 pc super(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 [image]. No >T8 dwarfs were discovered in the present cross-match, although less than one was expected in the limited area (2099 deg super(2)) of SDSS DR1.