Transcript Jets in the DR21/W75N Star Forming Region

Jonathan Rowles (contact: [email protected]); Michael D. Smith, Centre for Astrophysics
and Planetary Science, University of Kent, UK; Chris J. Davis, JAC, Hawaii
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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
Region B
Region C
Region D
Region E
This area is to the south of DR21.
This area is centered on
DR21(OH).
This area is centered on W75N.
This area is to the west of W75N.
This area is to the
west of DR21.
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