MOLECULAR OUTFLOWS ENTRAINED BY JET BOWSHOCKS

Recent high-resolution observations of CO outflows often reveal well-collimated emitting regions with radial velocities that increase away from the outflow source (''accelerating'' outflows), surrounded by limb-brightened low-velocity emission. There is growing evidence that molecular flows exhibiting this structure are driven by high-velocity, possibly time-variable, narrow jets. In order to better understand the dynamical interaction between such jets and the large-scale outflow, we present a simple, analytic model in which the molecular outflow corresponds 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 observed ''accelerating'' molecular flows. The model also gives global outflow shapes that are comparable to the observed ones, and predicts a higher collimation for less energetic flows (i.e. for lower luminosity sources), in agreement with reported trends.