Building the molecular cloud population: the role of cloud mergers
Building the molecular cloud population: the role of cloud mergers
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构建分子云群：云合并的作用
DOI：
10.1093/mnras/stac3627
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发表时间：
2022
影响因子：
4.8
通讯作者：
Goodman, Alyssa A.
中科院分区：
文献类型：
--
作者：
Skarbinski, Maya;Jeffreson, Sarah M. R.;Goodman, Alyssa A.
我们通过模拟一个类银河系的移动网格码区，研究了慢分子云合并的物理驱动因素，并确定了这些合并对星系云团的质量分布和恒星形成效率的影响。我们发现，这些合并中83%的 发生在相对速度低于5公里的 S−1，并与大规模原子气体流动有关，主要由超新星爆炸和银河系自转引起的热、电离气体气泡膨胀驱动。这些合并的主要效果是将分子质量聚集到更高质量的云中：合并占质量为2×106M 的云中包含的分子质量的50%以上。这些高质量星云的密度、内部速度弥散和瞬时恒星形成效率都比它们未合并的、低质量的前驱星体高。因此，我们模拟的星系的平均瞬时恒星形成效率，其合并率仅为每MYR云的1% ，比不含合并的类似云的数量高出25% 。
We study the physical drivers of slow molecular cloud mergers within a simulation of a Milky Way-like galaxy in the moving-mesh codearepo, and determine the influence of these mergers on the mass distribution and star formation efficiency of the galactic cloud population. We find that 83 per cent of these mergers occur at a relative velocity below 5 km s−1, and are associated with large-scale atomic gas flows, driven primarily by expanding bubbles of hot, ionized gas caused by supernova explosions and galactic rotation. The major effect of these mergers is to aggregate molecular mass into higher-mass clouds: mergers account for over 50 per cent of the molecular mass contained in clouds of massM> 2 × 106M⊙. These high-mass clouds have higher densities, internal velocity dispersions and instantaneous star formation efficiencies than their unmerged, lower mass precursors. As such, the mean instantaneous star formation efficiency in our simulated galaxy, with its merger rate of just 1 per cent of clouds per Myr, is 25 per cent higher than in a similar population of clouds containing no mergers.