CSO CO (2-1) and Spitzer IRAC observations of a bipolar outflow in high-mass star-forming

CSO CO (2-1) and Spitzer IRAC observations of a bipolar outflow in high-mass star-forming region

IRAS 22506+5944

Ze-Qiang Xie;Ke-Ping Qiu

【期刊名称】《天文和天体物理学研究》 【年(卷),期】2018(018)002

【摘要】We present Caltech Submillimeter Observatory CO (2-1) and Spitzer IRAC observations toward IRAS 22506+5944,which is a 104 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 km s-1) to moderate (～8-12km s-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