Massive Molecular Outflows at High Spatial Resolution

We present high-spatial resolution Plateau de Bure Interferometer CO(2-1) andSiO(2-1) observations of one intermediate-mass and one high-mass star-formingregion. The intermediate-mass region IRAS20293+3952 exhibits four molecularoutflows, one being as collimated as the highly collimated jet-like outflowsobserved in low-mass star formation sources. Furthermore, comparing the datawith additional infrared H2 and cm observations we see indications that thenearby ultracompact HII region triggers a shock wave interacting with theoutflow. The high-mass region IRAS19217+1651 exhibits a bipolar outflow as welland the region is dominated by the central driving source. Adding two moresources from the literature, we compare position-velocity diagrams of theintermediate- to high-mass sources with previous studies in the low-massregime. We find similar kinematic signatures, some sources can be explained byjet-driven outflows whereas other are better constrained by wind-driven models.The data also allow to estimate accretion rates varying from a few times10^{-5}Msun/yr for the intermediate-mass sources to a few times 10^{-4}Msun/yrfor the high-mass source, consistent with models explaining star formation ofall masses via accretion processes.Comment: 14 pages text, 4 tables, 8 figures, accepted for Ap