大质量恒星形成区样本外向流的高灵敏度搜寻

A Sensitive Survey of Dense Parts of Outflows toward Massive Cores

对13个大质量恒星形成区样本进行了SiO(2-1)、CH_3OH(2-1)和C^(34)S(2-1)热线的观测.在9个分子云核中,3条热线同时被探测到.这9个SiO探测中,有3个是新探测到的且它们强度都相对较弱.所有探测到的谱线都有较明显的线翼,这可能是外向流出现的证据.SiO谱线的线宽最宽,这也更进一步表明SiO辐射可能是来自高速的外向流,即更靠近外向流的激发源.估算了各分子谱线的旋转温度,柱密度和相对元素丰度.结果表明SiO和CH_3OH元素丰度之间有较好的相关性,相关系数R=0.77,但是SiO和C^(34)S元素丰度之间却没有任何相关性.

A sample of 13 massive star-forming cores was observed in SiO （2-1）, CH3OH （2- 1） and C34S （2-1） thermal lines. Nine of these cores were detected in all three lines. Among the nine SiO detections, three were new detections and were relatively faint. Most of the lines have wide wings, which might be interpreted as the evidence of ongoing energetic outflows in the cores. The line widths of SiO are generally the broadest, which might further suggest that SiO emissions are due to higher velocity outflow and are closer to the excited source. We derive the rotational temperatures, column densities, and chemical relative abundances of the cores. There is a strong correlation between SiO and CH3OH abundances, with correlation coefficient R = 0.77, but no correlation is observed between SiO and C34S.