Formation of globular cluster systems – II. Impact of the cut-off of the cluster initial mass function
Formation of globular cluster systems – II. Impact of the cut-off of the cluster initial mass function
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球状星团系统的形成 - II. 星团初始质量函数截止的影响
DOI：
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发表时间：
2018
影响因子：
4.8
通讯作者：
O. Gnedin
中科院分区：
文献类型：
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作者：
Nick Choksi;O. Gnedin
对年轻星团的观测表明，星团初始质量函数（CIMF）的高质量端偏离了纯粹的幂律，而是呈指数截断。我们通过更新我们的星团形成和演化分析模型来研究这种截断对球状星团（GC）系统形成的影响，该模型基于暗物质晕合并树和经验星系尺度关系，并且在之前的工作中已经显示出与广泛的观测数据相匹配。$M_c的截止质量=10^{6.5}M_{\odot}$或$10^{7}M_{\odot}$符合许多标度关系：GC系统质量与主晕质量之间的标度关系，GC系统的平均金属丰度与主晕质量之间的标度关系，以及星团质量的分布。这个M_c的范围与银河系外GC系统的间接测量值一致。$M_c<10^{6.5}M_{\odot}$的模型不能再现大质量星系中观测到的GC金属丰度和质量分布。当使用相同的方法测量时，所有$M_c$模型的贫金属团簇的质量-金属丰度关系的斜率（蓝色倾斜）与误差范围内的观测结果一致。我们引入了另一种更稳健的拟合方法，该方法揭示了低$M_c$的倾斜斜率增加的趋势。在我们的模型中，蓝色倾斜的出现是因为缺乏金属的星团形成于质量相对较低的星系中，这些星系缺乏足够的冷气体来对质量最高的CIMF进行取样。大质量的蓝色星团形成于质量越来越大的星系中，并继承了它们更高的金属丰度。富含金属的星系团没有表现出这样的倾斜，因为它们形成于质量大得多的星系中，这些星系有足够的冷气体来对CIMF进行充分的采样。
Observations of young star clusters reveal that the high-mass end of the cluster initial mass function (CIMF) deviates from a pure power-law and instead truncates exponentially. We investigate the effects of this truncation on the formation of globular cluster (GC) systems by updating our analytic model for cluster formation and evolution, which is based on dark matter halo merger trees coupled to empirical galactic scaling relations, and has been shown in previous work to match a wide array of observational data. The cutoff masses of $M_c=10^{6.5} M_{\odot}$ or $10^{7}M_{\odot}$ match many scaling relations: between the GC system mass and host halo mass, between the average metallicity of the GC system and host halo mass, and the distribution of cluster masses. This range of $M_c$ agrees with indirect measurements from extragalactic GC systems. Models with $M_c<10^{6.5}M_{\odot}$ cannot reproduce the observed GC metallicity and mass distributions in massive galaxies. The slope of the mass-metallicity relation for metal-poor clusters (blue tilt) for all $M_c$ models is consistent with observations within their errors, when measured using the same method. We introduce an alternative, more robust fitting method, which reveals a trend of increasing tilt slope for lower $M_c$. In our model the blue tilt arises because the metal-poor clusters form in relatively low-mass galaxies which lack sufficient cold gas to sample the CIMF at highest masses. Massive blue clusters form in progressively more massive galaxies and inherit their higher metallicity. The metal-rich clusters do not exhibit such a tilt because they form in significantly more massive galaxies, which have enough cold gas to fully sample the CIMF.
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
分子云、星团和高红移团块最大质量尺度的统一模型
影响因子：
4.8
作者：
Reina-Campos;Kruijssen
通讯作者：
Kruijssen