HIGH STAR FORMATION RATES IN TURBULENT ATOMIC-DOMINATED GAS IN THE INTERACTING GALAXIES IC 2163 AND NGC 2207
HIGH STAR FORMATION RATES IN TURBULENT ATOMIC-DOMINATED GAS IN THE INTERACTING GALAXIES IC 2163 AND NGC 2207
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相互作用星系 IC 2163 和 NGC 2207 中以原子为主的湍流气体中的高恒星形成率
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
S. Juneau
中科院分区：
文献类型：
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作者：
B. Elmegreen;M. Kaufman;F. Bournaud;D. Elmegreen;C. Struck;E. Brinks;S. Juneau
本文结合对相互作用星系IC 2163和NGC 2207的CO观测，以及HI、Hα和24 μm观测，研究了星星形成率（SFR）表面密度与气体表面密度的关系。超过一半的高SFR区域以HI为主。当与其他星系相比，这些HI占主导地位的地区有多余的SFR相对于他们的分子气体表面密度，但正常的SFR相对于他们的总气体表面密度。HI主导的区域主要位于NGC 2207的外部，那里的HI速度色散很高，为40-50 km s−1。我们认为，在这些地区的恒星形成云的信封在较低的密度比正常的，使他们主要是原子，和核心在较高的密度比正常的，因为高湍流马赫数。这与压缩、高马赫数紊流密度概率分布函数变平的理论预测是一致的。
CO observations of the interacting galaxies IC 2163 and NGC 2207 are combined with HI, Hα, and 24 μm observations to study the star formation rate (SFR) surface density as a function of the gas surface density. More than half of the high-SFR regions are HI dominated. When compared to other galaxies, these HI-dominated regions have excess SFRs relative to their molecular gas surface densities but normal SFRs relative to their total gas surface densities. The HI-dominated regions are mostly located in the outer part of NGC 2207 where the HI velocity dispersion is high, 40–50 km s−1. We suggest that the star-forming clouds in these regions have envelopes at lower densities than normal, making them predominantly atomic, and cores at higher densities than normal because of the high turbulent Mach numbers. This is consistent with theoretical predictions of a flattening in the density probability distribution function for compressive, high Mach number turbulence.