THE GROWTH OF GALAXY STELLAR MASS WITHIN DARK MATTER HALOS
THE GROWTH OF GALAXY STELLAR MASS WITHIN DARK MATTER HALOS
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暗物质晕内星系恒星质量的增长
DOI：
10.1088/0004-637x/746/2/145
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
Zheng Zheng
中科院分区：
文献类型：
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作者：
I. Zehavi;S. Patiri;Zheng Zheng
我们使用在 Millennium Run 模拟中实现的“MPA”和“Durham”半解析模型，研究星系中恒星质量随宿主晕质量的变化。对于这两个模型，中心星系的恒星质量随着低质量端晕质量的增加而迅速增加，而在所探测的三个红移（z∼0,1,2）处，较大质量晕中的恒星质量增加得更慢。当今质量小于∼1012 h−1 M☉的晕中，中央星系中大约45%的恒星质量已经存在于z∼1处，对于质量更大的晕，这一比例增加到∼65%。重子转化为恒星的效率随晕质量呈峰值分布，峰值位置从 z ∼ 1 到 z ∼ 0 向低质量方向移动。低质量晕中的恒星质量主要通过 z ∼ 1 以来的恒星形成而增长，而在高质量晕中，大部分恒星质量是通过合并聚集的，让人想起“缩小尺寸”。我们将我们的发现与斯隆数字巡天和 DEEP2 巡天的实证结果进行比较，利用星系聚类测量来研究星系演化。理论预测与这些现象学结果在定性上一致，但存在很大差异。最重要的一个问题涉及 z ∼ 1 处祖星系中已经存在的恒星数量，这在两个半解析模型中大约是两倍大。我们证明，从星系-光晕连接研究星系演化的方法在约束理论模型方面非常强大，并且可以指导未来星系演化建模的工作。相反，半解析模型在改进此类方法方面发挥着重要作用。
We study the evolution of stellar mass in galaxies as a function of host halo mass, using the “MPA” and “Durham” semi-analytic models, implemented on the Millennium Run simulation. For both models, the stellar mass of the central galaxies increases rapidly with halo mass at the low-mass end and more slowly in halos of larger masses at the three redshifts probed (z ∼ 0, 1, 2). About 45% of the stellar mass in central galaxies in present-day halos less massive than ∼1012 h−1 M☉ is already in place at z ∼ 1, and this fraction increases to ∼65% for more massive halos. The baryon conversion efficiency into stars has a peaked distribution with halo mass, and the peak location shifts toward lower mass from z ∼ 1 to z ∼ 0. The stellar mass in low-mass halos grows mostly by star formation since z ∼ 1, while in high-mass halos most of the stellar mass is assembled by mergers, reminiscent of “downsizing.” We compare our findings to empirical results from the Sloan Digital Sky Survey and DEEP2 surveys utilizing galaxy clustering measurements to study galaxy evolution. The theoretical predictions are in qualitative agreement with these phenomenological results, but there are large discrepancies. The most significant one concerns the number of stars already in place in the progenitor galaxies at z ∼ 1, which is about a factor of two larger in both semi-analytic models. We demonstrate that methods studying galaxy evolution from the galaxy–halo connection are powerful in constraining theoretical models and can guide future efforts of modeling galaxy evolution. Conversely, semi-analytic models serve an important role in improving such methods.