Meeting the Cool Neighbors. IX. The Luminosity Function of M7-L8 Ultracool Dwarfs in the Field
Abstract
We present a 20 pc, volume-limited sample of M7-L8 dwarfs created through spectroscopic follow-up of sources selected from the Two Micron All Sky Survey Second Incremental Release Point Source Catalog. In this paper we present optical spectroscopy of 198 candidate nearby ultracool dwarfs, including 12 late-M and L dwarfs likely to be within 20 pc of the Sun and 94 more distant late-type dwarfs. We have also identified five ultracool dwarfs with spectral signatures of low gravity. Combining these data with previous results, we define a sample of 99 ultracool dwarfs in 91 systems within 20 pc. These are used to estimate the J- and K-band luminosity functions for dwarfs with optical spectral types between M7 and L8 (10.5 < M_J < 15, 9.5 < M_(KS) < 13). We find a space density of 4.9 × 10^(-3) pc^(-3) for late-M dwarfs (M7-M9.5) and a lower limit of 3.8 × 10^(-3) pc^(-3) for L dwarfs.
Additional Information
© 2007 The American Astronomical Society. Received 2006 July 28; accepted 2006 September 23. We would like to acknowledge the numerous NOAO telescope operators and support staff at Kitt Peak, Cerro Tololo, Cerro Panchon, and Mauna Kea that made this work possible and endured our busy observing program: S. Adams, A. Alvarez, T. Beck, M. Bergmann, R. Carrasco, G. Doppmann, E. Eastburn, A. Fhima, B. Gillespie, P. Gomez, A. Guerra, M. Hainaut- Rouelle, H. Halbedel, D. Harmer, K. Labrie, L. Macri, H. Mathis, A. Matulonis, D. Maturana, S. Pizarro, P. Prado, K. Roth, K. Volk, and D. Willmarth. We also thank the NOAO Telescope Allocation committees for their enduring support of this project. We acknowledge Finlay Mungall for observing assistance. K. L. C. is supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under AST 04-01418. This research was partially supported by a grant from the NASA/NSF NStars initiative, administered by the Jet Propulsion Laboratory, Pasadena, CA. 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 Infrared Processing and Analysis Center, California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation; and from the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This research is based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium. This research is also based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq ( Brazil), and CONICET (Argentina). This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France.Attached Files
Published - CRUaj07.pdf
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Additional details
- Eprint ID
- 16624
- Resolver ID
- CaltechAUTHORS:20091109-101644923
- AST 04-01418
- NSF Astronomy and Astrophysics Fellowship
- NASA/JPL/Caltech
- Created
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2009-11-16Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)