MOLECULAR OUTFLOWS ENTRAINED BY JET BOWSHOCKS

Recent high-resolution observations of CO outflows often reveal well-c ollimated emitting regions with radial velocities that increase away f rom the outflow source (''accelerating'' outflows), surrounded by limb -brightened low-velocity emission. There is growing evidence that mole cular flows exhibiting this structure are driven by high-velocity, pos sibly time-variable, narrow jets. In order to better understand the dy namical interaction between such jets and the large-scale outflow, we present a simple, analytic model in which the molecular outflow corres ponds to environmental gas entrained in the wake of a bowshock created by an internal jet working surface. This model results in flows with velocity and density structures that appear to be similar to the obser ved ''accelerating'' molecular flows. The model also gives global outf low shapes that are comparable to the observed ones, and predicts a hi gher collimation for less energetic flows (i.e. for lower luminosity s ources), in agreement with reported trends.