High-Velocity Molecular Gas from High-Mass Star Formation Regions
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Abstract
We present results of a search for 12CO (J = 1-0) high-velocity line wings toward 122 high-mass star formation regions with the NRAO 12 m telescope. Of the 94 sources for which we obtained data suitable for interpretation of low-intensity line wings, fully 90% are associated with high-velocity (HV) gas in the beam. Ten percent have little or no HV gas (full width [FW] less than 15 km s-1 at the 1 σ TA* level), 49% have FWs between 15 and 30 km s-1, 30% have FWs between 30 and 45 km s1, and 11% have FWs greater than 45 km s-1. We find that the 12CO (J = 1-0) full widths are generally substantially larger than those seen toward low-mass stars. If the HV gas is due to bipolar outflows, then these results indicate that molecular outflows are a common property of newly formed massive stars, similar to the findings for low-mass stars. Two high-mass star formation regions with strong 12CO (J = 1-0) line wings, G25.65+1.05 and G240.31+0.07, were identified during the survey and mapped with the NRAO 12 m telescope. Each field of view contains an ultracompact H II region located on or near the flow axis of a massive and energetic bipolar outflow. The molecular outflows associated with these sources, like those associated with other massive-star formation regions, have several times more mass and momentum in their flows and ∼1 order of magnitude greater energies and luminosities than those associated with low-mass stars.