An analysis of water line profiles in star formation regions observed by the Submillimeter Wave Astronomy Satellite

We present spectral line profiles for the 557 GHz 1(10)-->1(01) ground-state rotational transition of ortho-(H2O)-O-16 for 18 Galactic star formation regions observed by the Submillimeter Wave Astronomy Satellite. Water is unambiguously detected in every source. The line profiles exhibit a wide variety of shapes, including single-peaked spectra and self-reversed profiles. We interpret these profiles using a Monte Carlo code to model the radiative transport. The observed variations in the line profiles can be explained by variations in the relative strengths of the bulk flow and small-scale turbulent motions within the clouds. Bulk flow (infall, outflow) must be present in some cloud cores, and in certain cases this bulk flow dominates the turbulent motions.