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arXiv 1809.01665astro-ph.GA
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IQ-合作实验室1.1:模拟中央星系的恒星形成序列

IQ-Collaboratory 1.1: the Star-Forming Sequence of Simulated Central Galaxies

ChangHoon Hahn, Tjitske K. Starkenburg, Ena Choi, Romeel Davé, Claire M. Dickey, Marla C. Geha, Shy Genel, Christopher C. Hayward, Ariyeh H. Maller, Nityasri Ma… 展开作者

ChangHoon Hahn, Tjitske K. Starkenburg, Ena Choi, Romeel Davé, Claire M. Dickey, Marla C. Geha, Shy Genel, Christopher C. Hayward, Ariyeh H. Maller, Nityasri Mandyam, Viraj Pandya, Gergö Popping, Mika Rafieferantsoa, Rachel S. Somerville, Jeremy L. Tinker

摘要:

恒星形成序列(SFS)是现代星系形成模型预测的星系性质空间的一个重要特征。我们提出了一个灵活的数据驱动的方法来确定这个SFS在很宽的范围内的恒星形成率和恒星质量使用高斯混合模型(GMM)。使用这种方法,我们提出了一个一致的比较的$z=0$ SFS的中心星系的Illustris,EAGLE和Mufasa流体动力学模拟和圣克鲁斯半解析模型(SC-SAM),旁边的数据从斯隆数字巡天。我们发现,令人惊讶的是,SFS的幅度变化高达${\sim} 0.7\,\mathrm{dex}$(${\sim} 5$的因素)之间的模拟与幂律斜率范围从$0.7$到$1.2$。除了SFS,我们的GMM方法还确定了子组件在恒星形成率恒星质量的关系,对应于恒星爆发,过渡,和静止的子种群。流体动力学模拟同样占主导地位的SFS和静态子种群不同的SC-SAM,它预测的过渡和恒星爆发星系的恒星质量以上和以下$10^{10} M_\odot$,分别占相当大的比例。所有的模拟也产生了大量的低质量静止的中央星系,这些星系与观测结果有明显的张力。这些结果表明,即使在模型中,以及再现许多可观的星系人口,$z=0$ SFS和其他子群体仍然显示出显着的差异,可以提供强大的约束星系形成模型。

英文摘要:

A tightly correlated star formation rate-stellar mass relation of star forming galaxies, or star-forming sequence (SFS), is a key feature in galaxy property-space that is predicted by modern galaxy formation models. We present a flexible data-driven approach for identifying this SFS over a wide range of star formation rates and stellar masses using Gaussian mixture modeling (GMM). Using this method, we present a consistent comparison of the $z=0$ SFSs of central galaxies in the Illustris, EAGLE, and Mufasa hydrodynamic simulations and the Santa Cruz semi-analytic model (SC-SAM), alongside data from the Sloan Digital Sky Survey. We find, surprisingly, that the amplitude of the SFS varies by up to ${\sim} 0.7\,\mathrm{dex}$ (factor of ${\sim} 5$) among the simulations with power-law slopes range from $0.7$ to $1.2$. In addition to the SFS, our GMM method also identifies sub-components in the star formation rate-stellar mass relation corresponding to star-burst, transitioning, and quiescent sub-populations. The hydrodynamic simulations are similarly dominated by SFS and quiescent sub-populations unlike the SC-SAM, which predicts substantial fractions of transitioning and star-burst galaxies at stellar masses above and below $10^{10} M_\odot$, respectively. All of the simulations also produce an abundance of low-mass quiescent central galaxies in apparent tension with observations. These results illustrate that, even among models that well reproduce many observables of the galaxy population, the $z=0$ SFS and other sub-populations still show marked differences that can provide strong constraints on galaxy formation models.

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