A Wide-Field Optical and Near-Infrared Search for Brown Dwarf Candidates

The Two Micron All Sky Survey (2MASS) has been a great resource for astronomers in search of low-mass objects. J, H, and K photometry from 2MASS has been used to pinpoint brown dwarf candidates by their distinctive near-infrared colors. We present a study which utilizes this resource in conjunction with overlapping I-band photometry from the Canada-France-Hawaii Telescope's 12,288 by 8,192 pixel mosaic CCD to isolate previously unidentified brown dwarf candidates based on their optical and near-infrared colors. Our selection criteria included a high signal to noise ratio in detections from both sources and a color range of 4 < I - J < 10 and J - K <= 1.5. This range corresponds to published estimates of the colors of late-type dwarfs and also excludes reddened background giants. This analysis produces 217 candidates that meet these criteria; their attributes and credibility are discussed. The group, representing spectral types from M9 to L6 or later, could contribute greatly to the current understanding of brown dwarfs if spectroscopically confirmed. Additionally, this study provides insight into the expectations of brown dwarf discoveries from the upcoming 3pi steradian Pan-STARRS survey. This work was conducted through a Research Experience for Undergraduates (REU) position at the University of Hawaii's Institute for Astronomy and funded by the NSF.