Radio Continuum and Methanol Observations of DR21(OH)
  We report high sensitivity sub-arcsecond angular resolution observations of
the massive star forming region DR21(OH) at 3.6, 1.3, and 0.7 cm obtained with
the Very Large Array. In addition, we conducted observations of CH3OH 44 GHz
masers. We detected more than 30 new maser components in the DR21(OH) region.
Most of the masers appear to trace a sequence of bow-shocks in a bipolar
outflow. The cm continuum observations reveal a cluster of radio sources; the
strongest emission is found toward the molecular core MM1. The radio sources in
MM1 are located about 5" north of the symmetry center of the CH3OH outflow, and
therefore, they are unlikely to be associated with the outflow. Instead, the
driving source of the outflow is likely located in the MM2 core. Although based
on circumstantial evidence, the radio continuum from MM1 appears to trace
free-free emission from shock-ionized gas in a jet. The orientation of the
putative jet in MM1 is approximately parallel to the CH3OH outflow and almost
perpendicular to the large scale molecular filament that connects DR21 and
DR21(OH). This suggests that the (accretion) disks associated with the
outflows/jets in the DR21 - DR21(OH) region have symmetry axes mostly
perpendicular to the filament.
