NRAO/Socorro Colloquium Series:
15 December 1995
Hélène R. Dickel
Univ. of Illinois at Urbana/Champaign
The Extremely Luminous DR21 Bipolar Outflow
The DR 21 star-forming region has the most massive and energetic
young stellar bipolar outflow in our Galaxy (shocked H2, shock enhanced
HCO+, CO, and HI). Very broad (FWHM~35 km/s) and deep (opacity ~3->6)
HI absorption lines are observed toward the continuum source DR 21 with the
VLA at a resolution of 5 arcsec. The HI absorption exhibits
negative-velocity wings which are associated with the high-velocity
outflow. The kinematics of the HI gas suggest that it is accelerating from
a position close to the west edge of HII component C and a nearby H2O
maser. A high negative velocity channel extends eastward from the outflow
source. The location of the source of the outflow as determined from HI
is similar to that derived from both CO kinematics and NH3 (3,3) clumps
with negative velocity wings.
A strong magnetic field of ~442 microGauss is detected in HI in the
outflowing gas. About 0.4 solar masses is involved in the HI absorption
outflow. The energetics of the DR 21 outflow are dominated by bulk
motions of the gas if the outflow has an inclination angle (to the plane
of the sky) of less than 20 degrees and by the magnetic field if the
inclination angle is greater than 20 degrees.
Friday, 15 December 1995
11:00am
Array Operations Center Auditorium
Local Host: Chris De Pree
Other NRAO/Socorro colloquia
mrupen@nrao.edu