THE IMPACT OF STELLAR FEEDBACK ON THE STRUCTURE, SIZE, AND MORPHOLOGY OF GALAXIES IN MILKY-WAY-SIZED DARK MATTER HALOS
THE IMPACT OF STELLAR FEEDBACK ON THE STRUCTURE, SIZE, AND MORPHOLOGY OF GALAXIES IN MILKY-WAY-SIZED DARK MATTER HALOS
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DOI：
10.3847/0004-637x/824/2/79
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发表时间：
2016-06-20
影响因子：
4.9
通讯作者：
Kravtsov, Andrey V.
中科院分区：
文献类型：
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作者：
Agertz, Oscar;Kravtsov, Andrey V.
我们使用从相同初始条件开始的银河系大小的晕中的宇宙放大模拟来研究星系大小、重子分数、形态和角动量在恒星形成-反馈周期的不同参数下的演化。我们的基准模型具有高的局部恒星形成效率，从而产生有效的反馈，产生了一个真实的晚型星系，它与晚型星系的基本属性的演化相匹配：恒星质量、盘大小、由运动冷盘主导的形态、恒星和气体表面密度分布以及特定角动量。我们认为，反馈在这一成功中的作用是双重的：(1)去除低角动量气体，(2)保持低的盘晕质量分数，这抑制了导致角动量重新分布和重子中心集中的盘不稳定性。然而，我们的模型具有较低的局部恒星形成效率，但每个超新星的能量输入很大，选择产生一个与我们的基准模型具有相似恒星形成历史的星系，导致一个高度不规则的星系没有运动冷分量，恒星分布过度扩大，角动量很低。这表明，只有当在致密的冷气体中通过局部有效的恒星形成而使反馈变得强烈时，所产生的星系大小、气体/恒星表面密度分布和恒星盘角动量才与观测到的z=0星系一致。
We use cosmological zoom-in simulations of galaxy formation in a Milky-Way-sized halo started from identical initial conditions to investigate the evolution of galaxy sizes, baryon fractions, morphologies, and angular momenta in runs with different parameters of the star formation-feedback cycle. Our fiducial model with a high local star formation efficiency, which results in efficient feedback, produces a realistic late-type galaxy that matches the evolution of basic properties of late-type galaxies: stellar mass, disk size, morphology dominated by a kinematically cold disk, stellar and gas surface density profiles, and specific angular momentum. We argue that feedback's role in this success is twofold: (1) removal of low angular momentum gas, and (2) maintaining a low disk-to-halo mass fraction, which suppresses disk instabilities that lead to angular momentum redistribution and a central concentration of baryons. However, our model with a low local star formation efficiency, but large energy input per supernova, chosen to produce a galaxy with a similar star formation history as our fiducial model, leads to a highly irregular galaxy with no kinematically cold component, overly extended stellar distribution, and low angular momentum. This indicates that only when feedback is allowed to become vigorous via locally efficient star formation in dense cold gas do resulting galaxy sizes, gas/stellar surface density profiles, and stellar disk angular momenta agree with observed z = 0 galaxies.