An extremely Luminous H2 Flow in the Dr21 Star Forming Region

Abstract

Previously, mapping of the spatial distribution and velocity structure of vibrational molecular hydrogen (H2) line emission has necessarily been restricted to the central outflow region of the Orion Molecular Cloud (e.g. Beckwidth et al. 1983) where the line intensities are an order of magnitude larger than any other presently known H2 emission source. However, an improved understanding of the role played by highly energetic gas flows in sustaining the observed H2 line emission relies heavily on the collection of comparable data on other active star-forming regions. With this view in mind, we have undertaken a detailed H2 line emission survey of the DR21/W75S molecular cloud complex. We considered this region to be one of the best candidates because it was already known to possess a luminosity (Harvey et al. 1977), CO wind velocities (Dickel et al. 1978, Fischer et al. 1985) and extended H2 emission (Fischer et al. 1981) similar to those seen in Orion.