A Significant Population of Candidate New Members of the Rho Ophiuchi
  Cluster
  We present a general method for identifying the pre-main-sequence population
of any star-forming region, unbiased with respect to the presence or absence of
disks, in contrast to samples selected primarily via their mid-infrared
emission from Spitzer surveys. We have applied this technique to a new, deep,
wide-field, near-infrared imaging survey of the Rho Ophiuchi cloud core to
search for candidate low mass members. In conjunction with published Spitzer
IRAC photometry, and least squares fits of model spectra (COND, DUSTY, NextGen,
and blackbody) to the observed spectral energy distributions, we have
identified 948 candidate cloud members within our 90% completeness limits of
J=20.0, H=20.0, and K_S=18.50. This population represents a factor of ~3
increase in the number of known young stellar objects in the Rho Ophiuchi
cloud. A large fraction of the candidate cluster members (81% +/- 3%) exhibit
infrared excess emission consistent with the presence of disks, thus
strengthening the possibility of their being bona fide cloud members.
Spectroscopic follow-up will confirm the nature of individual objects, better
constrain their parameters, and allow an initial mass function to be derived.
