Tanvi Sharma (Graduate Institute of Astronomy, NCU); Wen-Ping Chen (Graduate Institute of Astronomy, NCU); the W-band project members
Brown dwarfs, with spectral types later than about M6, have cool atmospheres (< 2800 K) to allow molecules, such as water and methane, to form. Here we present our effort to identify brown dwarf candidates in star-forming regions, i.e., when these objects are in infancy and are relatively hot and bright. By imaging photometry on-and-off the water absorption band near 1.45 microns, using a custom-made spectral (W) filter adapted to the CFHT-WIRCAM, together with data taken at J and H bands, we are able to distinguish water-bearing brown dwarfs against reddened field stars. We report the list of brown dwarf candidates in the Rho Oph cloud thus identified. Once spectroscopically confirmed, at least feasibly for the bright sources, the sample will be valuable, when compared with that of the known young stellar stars in the same region to shed light on the formation processes and early evolutionary in the broad stellar to substellar mass spectrum. The young brown dwarfs will also be useful for modeling of cool atmospheres (e.g., dust condensation).