Self-regulated star formation in galaxies via momentum input from massive stars
Self-regulated star formation in galaxies via momentum input from massive stars
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DOI：
10.1111/j.1365-2966.2011.19306.x
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发表时间：
2011-01
影响因子：
4.8
通讯作者：
P. Hopkins;E. Quataert;N. M. Berkeley;Cita
中科院分区：
文献类型：
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作者：
P. Hopkins;E. Quataert;N. M. Berkeley;Cita
来自大质量恒星的反馈被认为在塑造星系质量函数、星际介质（ISM）结构和星星形成的低效率方面起着关键作用，但反馈的确切形式是不确定的。在本文中，第一次在一个系列中，我们提出并测试一种新的数值实现恒星反馈的辐射，超新星和恒星风的动量传递到ISM。我们采用一个现实的冷却功能，并发现，大部分的气体冷却到100 K，使ISM变得高度不均匀。尽管如此，我们模拟的星系达到了一个近似的稳定状态，其中气体引力坍缩形成巨大的“分子”云（GMC），致密的团块和恒星;随后，恒星反馈分散GMC，重新填充弥漫的ISM。这种坍缩和扩散循环在小麦哲伦云（SMC）-类矮星、银河系和z 2星团圆盘类似物的模型中可见。模拟的全球星星形成效率与观测到的Kennicutt-Schmidt关系是一致的。此外，星星的形成率几乎不依赖于数值施加的高密度星星形成效率，密度阈值和密度标度。这是一个事实的结果，在我们的模拟中，星星的形成是由恒星反馈控制的，恒星反馈限制了可用于形成恒星的非常致密的气体的数量。相比之下，在没有恒星反馈的模拟中，即在只有重力和引力诱导的湍流的作用下，ISM经历失控坍缩到非常高的密度。在没有反馈的情况下，全球星星形成速率比观测到的星系星星形成速率高出1-2个数量级，表明恒星反馈对星系中星星形成的调节至关重要。
Feedback from massive stars is believed to play a critical role in shaping the galaxy mass function, the structure of the interstellar medium (ISM) and the low efficiency of star formation, but the exact form of the feedback is uncertain. In this paper, the first in a series, we present and test a novel numerical implementation of stellar feedback resulting from momentum imparted to the ISM by radiation, supernovae and stellar winds. We employ a realistic cooling function, and find that a large fraction of the gas cools to ≲100 K, so that the ISM becomes highly inhomogeneous. Despite this, our simulated galaxies reach an approximate steady state, in which gas gravitationally collapses to form giant ‘molecular’ clouds (GMCs), dense clumps and stars; subsequently, stellar feedback disperses the GMCs, repopulating the diffuse ISM. This collapse and dispersal cycle is seen in models of Small Magellanic Cloud (SMC)-like dwarfs, the Milky Way and z∼ 2 clumpy disc analogues. The simulated global star formation efficiencies are consistent with the observed Kennicutt–Schmidt relation. Moreover, the star formation rates are nearly independent of the numerically imposed high-density star formation efficiency, density threshold and density scaling. This is a consequence of the fact that, in our simulations, star formation is regulated by stellar feedback limiting the amount of very dense gas available for forming stars. In contrast, in simulations without stellar feedback, i.e. under the action of only gravity and gravitationally induced turbulence, the ISM experiences runaway collapse to very high densities. In these simulations without feedback, the global star formation rates exceed observed galactic star formation rates by 1–2 orders of magnitude, demonstrating that stellar feedback is crucial to the regulation of star formation in galaxies.