Jet driven molecular outflows in Orion

We present high sensitivity and high angular resolution images of the high velocity (upsilon(LSR) > 30 km s(-1)) CO emission in the J = 1 --> 0 and J = 2 --> 1 lines of the Orion KL region. These results reveal the morphology of the high-velocity CO emission at the most extreme velocities. High velo city emission has only been detected in two regions: BN/KL (IRc2/I) and Ori on-S. The Orion-S region contains a very young (dynamical age of similar to 10(3) years), very fast (similar to 110 km s(-1)) and very compact (less than or similar to 0.16 pc) bipolar outflow, From the morphology of the high-veloc ity gas we estimate that the position of the powering source must be 20 " n orth of FIR 4. So far, the exciting source of this outflow has not been det ected. For the IRc2/I molecular outflow the morphology of the moderate velo city (less than or similar to 60 km s(-1)) gas shows a weak bipolarity arou nd IRc2/I. The gas at the most extreme velocities does not show any bipolar ity around IRc2/I, if any, it is found similar to 30 " north from these sou rces. The blue and redshifted gas at moderate velocities shows similar spat ial distribution with a systematic trend for the size of the high-velocity gas to decrease as the terminal radial velocity increases. The same trend i s also found for the jet driven molecular outflows L 1448 and IRAS 03282 3035. The size-velocity relationship is fitted with a simple velocity law w hich considers a highly collimated jet and entrained material outside the j et moving in the radial direction. We also find that most of the CO outflow ing at moderate velocities is located at the head of the jet. Our results a nd the spatial distribution and kinematics of the shock tracers in this out flow can be explained if the IRc2/I outflow is driven by a precessing jet o riented along the line of sight. The implication of these findings in the e volution of molecular outflows is discussed.