| 摘 要： | We present Caltech Submillimeter Observatory CO(2–1) and Spitzer IRAC observations toward IRAS 22506+5944, which is a 10~4 L_⊙massive star-forming region. The CO(2–1) maps show an east-west bipolar molecular outflow originating from the 3 mm dust continuum peak. The Spitzer IRAC color-composite image reveals a pair of bow-shaped tips which are prominent in excess 4.5 μm emission and are located at the leading fronts of the bipolar outflow, providing compelling evidence for the existence of bow-shocks as the driving agents of the molecular outflow. By comparing our CO(2–1) observations with previously published CO(1–0) data, we find that the CO(2–1)/(1–0) line ratio increases from low(~5 kms~(-1)) to moderate(~8–12 kms~(-1)) velocities, and then decreases at higher velocities. This is qualitatively consistent with the scenario that the molecular outflow is driven by multiple bow-shocks. We also revisit the position-velocity diagram of the CO(1–0) data, and find two spur structures along the outflow axis, which are further evidence for the presence of multiple jet bowshocks. Finally, power-law fittings to the mass spectrum of the outflow gives power law indexes more consistent with the jet bow-shock model than the wide-angle wind model.
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