High-Resolution Imaging of CO Outflows in OMC-2 and OMC-3

A large-scale, high-resolution map of CO (1-0) emission toward the OMC-2 and OMC-3 star-forming regions is presented. The map is a mosaic of 46 fields using the Berkeley-Illinois-Maryland Array (BIMA) and covers ~10′ × 15′ at ~10'' resolution. These data are combined with single-dish FCRAO observations and analyzed to identify and determine the properties of nine protostellar outflows. The BIMA data alone almost completely resolve out the cloud emission at central velocities and only recover 1/20 of the flux in the high-velocity gas, showing that outflows are generally broadly dispersed over ~1' angular scales. All nine identified outflows emanate from known Class 0 or borderline Class 0/I sources, are associated with knots of shocked H2 emission, and have short dynamical times. It is suggested that only the youngest, most spatially compact, and energetic outflows have been found and that more distributed high-velocity gas undetected by BIMA is due to older outflows continuing through the Class I phase of protostellar evolution. The mechanical energy injection rate into the cloud is estimated to be ~1.5 L☉, which is comparable to the turbulent energy dissipation rate. Outflows appear capable, therefore, of sustaining cloud turbulence but a high star formation rate is required, implying a short cloud lifetime of ≤5 Myr.

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