High-Resolution CO Observations of the Molecular Outflow in the Orion IRc2 Region

We present high-spatial resolution (3"-5") interferometer data combined with single-dish maps of the CO J = 1-0 emission from the powerful molecular outflow originating near Orion IRc2. The outflow lobes are spatially resolved, weakly bipolar, poorly collimated, and we find no evidence for a jetlike molecular outflow. Instead, the CO outflow lobes fill a wide (≥ 130°) opening angle biconical flow, surrounding the Herbig-Haro objects and shocked H2 knots. The overall structure of the outflow is strongly affected by the dumpiness of the ambient gas. In particular, it seems that the lobe to the southeast is partly blocked by dense gas in the hot core. None of the current jet or wind outflow models are sufficient to explain the kinematics of the OMC 1 outflow. However, we suggest that a simple biconical flow model, in which the flow to the southeast is partly truncated by the hot core, is consistent with the data.