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D. L. Padgett (SIRTF Science Center), K. R. Stapelfeldt (Jet Propulsion Laboratory), A. F. Sargent (California Institute of Technology)
During the past several years, Hubble Space Telescope (HST) optical (WFPC2) and near-infrared (NICMOS) observations have provided the first detailed images of pre-main sequence circumstellar environments at spatial resolutions of 10-20 AU. Elongated reflection nebulosities and dark absorption lanes strongly suggest that optically thick circumstellar disks are seen in association with several young stars in nearby molecular clouds. However, longer wavelength observations are essential to confirm the presence and demonstrate the kinematic state of dense material in these systems. In hopes of better understanding nearby prototype disk systems, we have embarked on a project using the Owens Valley Millimeter Array to map the circumstellar gas and dust emission in systems where HST has resolved disk-like nebulosities. Three edge-on disks have been studied to date at 1-2 arcsec resolution: DG Tauri B, IRAS 04302+2247, and HH 30. The results show that dense gas tracers extend along the same position angle and have similar extent to the dust lanes observed by HST. In addition, the CO isotopomer channel maps show a velocity gradient primarily along the major axis of their molecular bars, indicating rotation in each source. The results support the interpretation of the circumstellar dust lanes as rotating disks.