Jets in the DR21/W75N Star Forming Region

1. Jets in the DR21/W75N Star Forming Region Jonathan Rowles (contact: jr219@kent.ac.uk); Michael D. Smith, Centre for Astrophysics and Planetary Science, University of Kent, UK; Chris J. Davis, JAC, Hawaii . Motivation: Velocity information can (1) establish a kinematic distance for an outflow, thereby allowing us to confidently associate a jet with a specific molecular cloud, and (2) distinguish red and blue-shifted lobes, so that we can identify the likely locations of outflow sources. We now know that H2 usually traces gas at low, near systemic, velocities (e.g. Davis & Smith 1996a, 1996b; Davis et al. 2000, 2004). This is because, in C-shocks or in the magnetic precursors of J-shocks, H2 emission is rapidly heated and radiatively cooled before the gas can be accelerated to high outflow velocities. Consequently, in H2 only modest velocities of ~10-30 km/s are recorded in the blue- and red-shifted lobes of outflows. The median H2 flow velocity is therefore a useful measure of the kinematic distance, while at the same time, the small velocity shifts are sufficient to allow identification of the jet and counter-jet components. Ultimately, our goal is to establish an unbiased census of outflows across the DR21/W75 region. Distances and source identifications are obviously a vital element when characterising the newly-discovered flows. With these combined outflow observations and JHK+ Spitzer photometry of the sources we will look for correlations between the YSO population and outflow size, luminosity, and/or propensity. Only then can the global properties of this high-mass star forming region be established. Method:We present data for 27 collimated outflows contained in the DR21 and W75N high mass star forming complex, observed using the CGS4 instrument on UKIRT. Status: The position-velocity diagrams presented below are associated with slits aligned with the jet axes. They illustrate a wide range of jet shock behaviour including forward and reverse shock waves, bow shocks and velocity gradients. Full results and implications are now being considered. Region A This area is to the south of DR21. Region B This area is centered on DR21(OH). Region C This area is centered on W75N. Region D This area is to the west of W75N. Region E This area is to the west of DR21. P