Interferometric measurements of the millimeter-wave dust emission from OMC-1

A high-resolution map of 113 GHz dust continuum emission from OMC-1 is presented. Maps in several bands confirm the detection of true continuum, free of contamination by molecular lines. The emission arises from a region approximately 10 arcsec in extent centered on IRc2 and coincident with the region of NH3 emission detected at the VLA. The peak column density near IRc2 is N(H2) = 10 to the 24th/sq cm. No continuum flux was detected from the SO emission region, indicating the column density there is less than 10 to the 23rd/sq cm. This suggests that the SO emission, previously modeled as a high-density torus surrounding IRc2, arises from a zone of abnormally high SO/H2 abundance at the surface of cavity around IRc2. In this new picture, the hot core is viewed as dense clumps of gas and dust left behind as the cavity was cleared by winds from IRc2. 27 references.