THE DETECTION OF [C-I] IN MOLECULAR OUTFLOWS ASSOCIATED WITH YOUNG STELLAR OBJECTS

The first observations of atomic carbon in molecular outflows are pres ented. Most of the outflow regions show similar [C I] and (CO)-C-13 li ne profiles suggesting the [C I] emission from outflow sources traces the same volume of gas as the CO emission, as previous studies have su ggested for molecular clouds in general. The [C I] and CO column densi ties for the 11 sources surveyed are computed over wing and line cente r velocities. If the [C I] column densities derived from line center v elocities are probing conditions in the ambient cloud in the vicinity of the infrared source, then a comparison of these values indicates th e carbon abundance in the low-velocity component of the outflows is es sentially the same as in the ambient cloud; there is no evidence for s hock enhancement of [C I] in the swept-up material. A map of the [C I] emission from the central arcminute of the luminous DR 21 outflow is presented. The [C I] emission is detected from the two CO outflow lobe s; [C I] emission from the southwest lobe appears as a limb-brightened , conical shell. Outflow parameters derived from [C I] are consistent with those derived from CO, suggesting the [C I] emission arises from ambient cloud material swept-up by the outflow. The presence of carbon in the swept-up component of the outflows indicates that gas phase ca rbon is present deep within molecular clouds and is not confined solel y to surface layers.