AAS 201st Meeting, January, 2003
Session 46. Planetary Systems: Observations and Models
Poster, Tuesday, January 7, 2003, 9:20am-6:30pm, Exhibit Hall AB

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[46.05U] Potential Brown Dwarfs Discovered in IfA Deep Imaging Survey

M. Graham (Oklahoma State University)

Deep, wide-field imaging surveys in the red and near-infrared are ideal for discovering substellar objects like brown dwarfs. A few of these surveys, such as 2MASS and SDSS, have already been successful in these attempts. A new wide-field red plus near-infrared survey was conducted by astronomers at the University of Hawaii's Institute for Astronomy (IfA) on the Subaru telescope. Five fields, each approximately 0.5 square degrees at varying galactic latitudes were observed in the Rc-, Ic-, and z'-bands.

Typical image quality of the survey is FWHM = 0.8". The total integration times for the Rc-, Ic-, and z'-bands were approximately 4500, 6500, and 9500 sec, respectively, for each field. For a 2" circular aperture the 5-sigma limiting magnitudes in Rc, Ic, and z' were approximately 27.1, 26.7, and 26.0, respectively.

One of the goals of the survey is the study of brown dwarfs. T dwarfs (or methane dwarfs) are the coolest, faintest, and most difficult to observe of the brown dwarf types. One T dwarf with spectral type T3-T4, IfA 0230-Z1, has already been confirmed from the IfA survey. In total the survey is expected to yield about 40 such objects.

Evaluation of the data has led to a large number of brown dwarf candidates. From four of the five fields in the survey, concentrating on the brightest (z'-magnitude < 23.0) stellar objects, approximately 38 excellent brown dwarf candidates were discovered. These are thought to be mostly late-L and T dwarfs.

This project was undertaken at the IfA as part of the summer 2002 Research Experience for Undergraduates program sponsored by the National Science Foundation. The presenter wishes to thank his project advisor at the IfA, Dr. Richard Wainscoat, as well as Dr. Eduardo Martin, who proposed the project as part of the IfA Deep Imaging Survey.

The author(s) of this abstract have provided an email address for comments about the abstract: mcg@okstate.edu

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