Small-scale structure in the DR 21/DR 21 (OH) region : a high resolution continuum study at millimetre and submillimetre wavelengths.

The DR 21 and DR 21(OH) dense cloud cores have been mapped at continuum wavelengths of 800 and 1100 microns. Four distinct sources previously unresolved at these wavelengths are seen in DR 21(OH) which have masses of about 1000 solar masses each within regions of size about 0.2 pc. The most massive of these is optically thick even at 350 microns. The more evolved region DR 21 has a similar total mass, but shows less direct evidence of small-scale structure at this spatial resolution. This region is more active, with H II regions and newly formed stars. The millimeter and submillimeter emission is elongated in a direction approximately perpendicular to that of the outflow. The masses of DR 21 and DR 21(OH) are estimated to be 20,000 solar and 16,000 solar, respectively. The dynamics and energetics of both cloud cores are discussed.