分子云中两个微米全天巡天团的旋转
Rotation of Two Micron All Sky Survey Clumps in Molecular Clouds
摘要：
本文利用五院射电天文台13.7米射电望远镜的$^{13}$ CO（1- 0）和C $^{18}$ O（1- 0）图分析了12个团簇的转动性质。位于分子云中的团簇的半径（$R$）在0.06 - 0.271，pc范围内。团块伸长的方向与速度梯度的方向无关。根据$^{13}$ CO图像和C $^{18}$ O图像，我们测量了比角动量（J/M）在0.0022和0.025 pc\，km\，s之间的$^{-1}$。基于不同示踪剂的$J/M$的一致性表明，尽管不透明度显著不同，但致密团块中的$^{13}$ CO和C $^{18}$ O基本上示踪相同的物质。我们还发现$J/M$作为$R$的函数以幂律形式$J/M~\propto~R^{1.58~\pm~0.11}$单调增加。自转能与引力能之比$β$的范围为0.0012至0.018。$β$的小值意味着，单独的旋转不足以支撑团块抵抗引力坍缩。
英文摘要：
We have analyzed the rotational properties of 12 clumps using $^{13}$CO (1--0) and C$^{18}$O (1--0) maps of the Five College Radio Astronomy Observatory 13.7 m radio telescope. The clumps, located within molecular clouds, have radii ($R$) in the range of 0.06 -- 0.27\,pc. The direction of clump elongation is not correlated with the direction of the velocity gradient. We measured the specific angular momentum (J/M) to be between 0.0022 and 0.025 pc\,km\,s$^{-1}$ based on $^{13}$CO images, and between 0.0025 and 0.021 pc\,km\,s$^{-1}$ based on C$^{18}$O images. The consistency of $J/M$ based on different tracers indicates the $^{13}$CO and C$^{18}$O in dense clumps trace essentially the same material despite significantly different opacities. We also found that $J/M$ increases monotonically as a function of $R$ in power--law form, $J/M~\propto~R^{1.58~\pm~0.11}$. The ratio between rotation energy and gravitational energy, $β$, ranges from 0.0012 to 0.018. The small values of $β$ imply that rotation alone is not sufficient to support the clump against gravitational collapse.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
