arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2009.12467astro-ph.GA
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如何经验地模拟暗物质晕中的恒星形成:I。从数值模拟推断中心星系

How to empirically model star formation in dark matter halos: I. Inferences about central galaxies from numerical simulations

Yangyao Chen, H. J. Mo, Cheng Li, Kai Wang

摘要:

我们使用TNG和EAGLE流体动力学模拟研究中心星系-暗物质晕的关系,需要一个基于晕的经验模型的恒星形成的星系。利用线性降维算法和模型系综方法,我们发现,无论是恒星形成和淬火星系,恒星形成历史(SFH)是密切相关的晕质量组装历史(MAH)。低质量星系的猝灭主要是由于与附近大质量晕相关的下落-喷射过程,而高质量星系的猝灭则与其宿主晕中大质量祖星系的形成密切相关。恒星形成和猝灭人口的分类的基础上,单独的晕属性包含污染所产生的样本不平衡和重叠分布的两个人口。在流体动力学模拟结果的指导下,我们建立了一个基于主晕马赫数的中央星系SFH的经验模型,并分别对恒星形成和猝灭粒子数进行了模拟。我们的模型是基于采用恒星形成模板从流体动力学模拟,以减少模型的复杂性的想法。我们使用各种测试来证明该模型可以恢复单个星系的恒星形成历史,并可以统计地再现星系双峰分布,恒星质量-晕质量和恒星形成率-晕质量关系从低到高红移,以及组装偏差。我们的研究提供了一个框架,使用流体动力学模拟发现,并激励使用,关键成分模型星系形成使用晕属性。

英文摘要:

We use TNG and EAGLE hydrodynamic simulations to investigate the central galaxy - dark matter halo relations that are needed for a halo-based empirical model of star formation in galaxies. Using a linear dimension reduction algorithm and a model ensemble method, we find that for both star-forming and quenched galaxies, the star formation history (SFH) is tightly related to the halo mass assembly history (MAH). The quenching of a low-mass galaxy is mainly due to the infall-ejection process related to a nearby massive halo, while the quenching of a high-mass galaxy is closely related to the formation of a massive progenitor in its host halo. The classification of star-forming and quenched populations based solely on halo properties contains contamination produced by sample imbalance and overlapping distributions of the two populations. Guided by the results from hydrodynamic simulations, we build an empirical model to predict the SFH of central galaxies based on the MAH of their host halos, and we model the star-forming and quenched populations separately. Our model is based on the idea of adopting star formation templates from hydrodynamic simulations to reduce model complexity. We use various tests to demonstrate that the model can recover star formation histories of individual galaxies, and can statistically reproduce the galaxy bimodal distribution, stellar mass - halo mass and star formation rate - halo mass relations from low to high redshift, and assembly bias. Our study provides a framework of using hydrodynamic simulations to discover, and to motivate the use of, key ingredients to model galaxy formation using halo properties.

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