Apex CO (9-8) mapping of an extremely high velocity and jet-like outflow in a high-mass star-forming region

Abstract

Atacama Pathfinder Experiment (APEX) mapping observations in CO (9-8) and (4-3) toward a high-mass star-forming region, NGC 6334 I, are presented. The CO(9-8) map has a 6″.4 resolution, revealing a ∼0.5pc, jet-like, and bipolar outflow. This is the first map of a molecular outflow in a THz line. The CO(9-8) and (4-3) lines arising from the outflow lobes both show extremely high velocity line wings, and their ratios indicate a gas temperature greater than 100K and a density higher than 104cm-3. The spatial-velocity structure of the CO(9-8) data is typical of a bow-shock-driven flow, which is consistent with the association between the bipolar outflow and the infrared bow-shaped tips. In short, the observations unveil a highly excited and collimated component in a bipolar outflow that is powered by a high-mass protostar, and provide insights into the driving mechanism of the outflow. Meanwhile, the observations demonstrate that high-quality mapping observations can be performed with the new THz receiver on APEX. © 2011. The American Astronomical Society. All rights reserved.