ANGULAR MOMENTUM IN GIANT MOLECULAR CLOUDS. I. THE MILKY WAY
ANGULAR MOMENTUM IN GIANT MOLECULAR CLOUDS. I. THE MILKY WAY
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巨型分子云中的角动量。
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
L. Blitz
中科院分区：
文献类型：
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作者：
N. Imara;L. Blitz
我们提出了一个详细的分析，比较在分子云和原子气体，围绕他们的速度场，以解决梯度的起源。为此，我们提出了分子云和周围原子气体的第一时刻强度加权速度图。这些地图是由莱顿/阿根廷/波恩银河系H i巡天的高分辨率13 CO观测和21厘米观测制作的。我们发现：（1）与每个分子云相关的原子气体具有相当大的速度梯度--范围从0.02到0.07 km s-1 pc-1--无论分子云本身是否具有相当大的线性梯度。(2)如果分子和原子气体中的梯度是由于旋转，这将意味着分子云的比角动量比周围的H i小1-6倍。(3)最重要的是，分子和原子气体中的速度梯度位置角通常相差很大，在玫瑰花分子云的情况下相差多达130°。这一结果反驳了分子云是由原子气体简单的自上而下坍缩形成的假设。
We present a detailed analysis comparing the velocity fields in molecular clouds and the atomic gas that surrounds them in order to address the origin of the gradients. To that end, we present first-moment intensity-weighted velocity maps of the molecular clouds and surrounding atomic gas. The maps are made from high-resolution 13CO observations and 21 cm observations from the Leiden/Argentine/Bonn Galactic H i Survey. We find that (1) the atomic gas associated with each molecular cloud has a substantial velocity gradient—ranging from 0.02 to 0.07 km s−1 pc−1—whether or not the molecular cloud itself has a substantial linear gradient. (2) If the gradients in the molecular and atomic gas were due to rotation, this would imply that the molecular clouds have less specific angular momentum than the surrounding H i by a factor of 1–6. (3) Most importantly, the velocity gradient position angles in the molecular and atomic gas are generally widely separated—by as much as 130° in the case of the Rosette molecular cloud. This result argues against the hypothesis that molecular clouds formed by simple top-down collapse from atomic gas.
影响因子：
6.5
作者：
K. Menten;M. Reid;J. Forbrich;J. Forbrich;A. Brunthaler
通讯作者：
K. Menten;M. Reid;J. Forbrich;J. Forbrich;A. Brunthaler