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arXiv 0903.4682astro-ph.CO
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恒星质量与晕质量关系在低和高红移下的限制

Constraints on the relationship between stellar mass and halo mass at low and high redshift

Benjamin P. Moster, Rachel S. Somerville, Christian Maulbetsch, Frank C. van den Bosch, Andrea V. Maccio', Thorsten Naab, Ludwig Oser

摘要:

我们使用统计方法来确定星系的恒星质量和它们所处的暗物质晕质量之间的关系。我们得到一个参数化的恒星晕质量(SHM)的关系,通过填充晕和subhalos在N体模拟星系,并要求所观察到的恒星质量函数被复制。我们发现很好的协议与限制星系星系透镜和半解析模型的预测。使用此映射,和从模拟中获得的晕和subhalos的位置,我们发现,我们的模型预测的星系两点关联函数(CF)作为恒星质量的函数是在SDSS中观察到的聚类特性在z=0非常吻合。我们表明,聚类数据不提供额外的强约束的SHM功能,并得出结论,我们的模型可以预测集群作为恒星质量的函数。我们计算条件质量函数,它产生的平均数量的星系与恒星质量的范围内[m,m+dm],居住在晕的质量M。我们研究了红移的SHM关系,并表明,低质量的晕,SHM比是较低的红移。导出的SHM关系被用来预测恒星质量依赖的星系CF和高红移的偏差。我们的模型预测,不仅是大质量的星系比低质量的更偏向于在所有的红移,但偏见增加更迅速地增加大质量的星系比低质量的红移。我们提出了方便的拟合函数SHM关系作为一个函数的红移,条件质量函数,作为恒星质量和红移的函数的偏差。

英文摘要:

We use a statistical approach to determine the relationship between the stellar masses of galaxies and the masses of the dark matter halos in which they reside. We obtain a parameterized stellar-to-halo mass (SHM) relation by populating halos and subhalos in an N-body simulation with galaxies and requiring that the observed stellar mass function be reproduced. We find good agreement with constraints from galaxy-galaxy lensing and predictions of semi-analytic models. Using this mapping, and the positions of the halos and subhalos obtained from the simulation, we find that our model predictions for the galaxy two-point correlation function (CF) as a function of stellar mass are in excellent agreement with the observed clustering properties in the SDSS at z=0. We show that the clustering data do not provide additional strong constraints on the SHM function and conclude that our model can therefore predict clustering as a function of stellar mass. We compute the conditional mass function, which yields the average number of galaxies with stellar masses in the range [m, m+dm] that reside in a halo of mass M. We study the redshift dependence of the SHM relation and show that, for low mass halos, the SHM ratio is lower at higher redshift. The derived SHM relation is used to predict the stellar mass dependent galaxy CF and bias at high redshift. Our model predicts that not only are massive galaxies more biased than low mass ones at all redshifts, but the bias increases more rapidly with increasing redshift for massive galaxies than for low mass ones. We present convenient fitting functions for the SHM relation as a function of redshift, the conditional mass function, and the bias as a function of stellar mass and redshift.

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