Star Cluster Formation in Cosmological Simulations. II. Effects of Star Formation Efficiency and Stellar Feedback
Star Cluster Formation in Cosmological Simulations. II. Effects of Star Formation Efficiency and Stellar Feedback
复制标题
宇宙学模拟中的星团形成。
作者：
Hui Li;O. Gnedin;N. Gnedin
在宇宙学模拟中，星星形成和恒星反馈的实现在塑造星系性质方面起着关键作用。在该系列的第一篇论文中，我们提出了一种新的方法来模拟星星的形成，作为一个星星集群的集合。在本文中，我们通过消除吸积间隙，提高动量反馈，并引入一个亚网格的初始绑定分数，fi，区分集群质量从恒星粒子质量改进的算法。我们进行了一套模拟与不同的星星形成效率每自由落体时间和超新星动量反馈强度。我们发现，银河系大小的星系的星星形成历史是敏感的，这使我们能够限制其值，在目前的模拟设置。从几个百分点到200%的变化对全球星系的性质几乎没有影响。然而，在较小的尺度上，星星团的性质对。我们发现，fi增加和集群质量。通过对fi的依赖性，团簇初始质量函数的形状随着。成团星星形成率和最大星团质量随星星形成率表面密度的增加而增加，两者关系的归一化依赖于。团簇形成的时间尺度系统地随着增加而减小。气体吸积历史的局部变化导致积分团簇形成效率的0.25 dex分散。来自所有观测量的联合约束更喜欢产生16%的中值积分效率的运行。
The implementation of star formation and stellar feedback in cosmological simulations plays a critical role in shaping galaxy properties. In the first paper of the series, we presented a new method to model star formation as a collection of star clusters. In this paper, we improve the algorithm by eliminating accretion gaps, boosting momentum feedback, and introducing a subgrid initial bound fraction, fi, that distinguishes cluster mass from stellar particle mass. We perform a suite of simulations with different star formation efficiency per freefall time and supernova momentum feedback intensity . We find that the star formation history of a Milky Way–sized galaxy is sensitive to , which allows us to constrain its value, , in the current simulation setup. Changing from a few percent to 200% has little effect on global galaxy properties. However, on smaller scales, the properties of star clusters are very sensitive to . We find that fi increases with and cluster mass. Through the dependence on fi, the shape of the cluster initial mass function varies strongly with . The fraction of clustered star formation and maximum cluster mass increase with the star formation rate surface density, with the normalization of both relations dependent on . The cluster formation timescale systematically decreases with increasing . Local variations in the gas accretion history lead to a 0.25 dex scatter for the integral cluster formation efficiency. Joint constraints from all the observables prefer the runs that produce a median integral efficiency of 16%.
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DOI：
10.1088/0004-637x/768/1/74
发表时间：
2012-11
期刊：
The Astrophysical Journal
影响因子：
--
作者：
L. Tacconi;R. Neri;R. Genzel;F. Combes;A. Bolatto;M. Cooper;S. Wuyts;F. Bournaud;A. Burkert-
通讯作者：
L. Tacconi;R. Neri;R. Genzel;F. Combes;A. Bolatto;M. Cooper;S. Wuyts;F. Bournaud;A. Burkert-
影响因子：
64.8
作者：
M. Vogelsberger;S. Genel;V. Springel;P. Torrey;D. Sijacki;Da Xu;G. Snyder;Simeon Bird;D. Nelson;Lars Hernquist Mit;HarvardCfA;Hits;I. Cambridge;Stsci;Ias Princeton
通讯作者：
M. Vogelsberger;S. Genel;V. Springel;P. Torrey;D. Sijacki;Da Xu;G. Snyder;Simeon Bird;D. Nelson;Lars Hernquist Mit;HarvardCfA;Hits;I. Cambridge;Stsci;Ias Princeton
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.
DOI：
10.1088/2041-8205/730/2/l13
发表时间：
2011-02
期刊：
The Astrophysical Journal Letters
影响因子：
--
作者：
F. Bigiel;A. Leroy;F. Walter;E. Brinks;W. D. Blok;C. Kramer;H. Rix;A. Schruba;K. Schuster;A. Usero;H. Wiesemeyer
通讯作者：
F. Bigiel;A. Leroy;F. Walter;E. Brinks;W. D. Blok;C. Kramer;H. Rix;A. Schruba;K. Schuster;A. Usero;H. Wiesemeyer
影响因子：
4.8
作者：
Hollyhead, K.;Bastian, N.;Gazak, Z.
通讯作者：
Gazak, Z.