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arXiv 1502.01348astro-ph.CO
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PRIMUS:通过交叉相关研究物理尺度对星系团光度依赖性的影响

PRIMUS: The Effect of Physical Scale on the Luminosity-Dependence of Galaxy Clustering via Cross-Correlations

Aaron D. Bray, Daniel J. Eisenstein, Ramin A. Skibba, Michael R. Blanton, Alison L. Coil, Richard J. Cool, Alexander J. Mendez, John Moustakas, Guangtun Zhu

摘要:

我们报告小规模的聚类测量从PRIMUS光谱红移调查的颜色和光度的函数。我们测量了62,106个具有PRIMUS红移的主星系和545,000个测光星系的示踪人口在z=0.2到z=1的红移之间的实空间交叉相关。我们分别适合一个幂律模型的红移和光度的三个独立的颜色选择的星系样本。我们报告在z=0.5和L=1.5 L* 的基准值处的聚类幅度。红色星系的聚集强度是蓝色星系的3倍,是绿色星系的1.5倍。我们还发现,集群的光度依赖性是强烈依赖于物理尺度,与更大的光度依赖性被发现之间的r=0.0625 Mpc/h和r=0.25 Mpc/h,相比r=0.5 Mpc/h到r=2 Mpc/h的范围。此外,在两个数量级的光度范围内,一个单一的幂律拟合的光度依赖性是不足以解释集群的增加,在明亮和暗淡的两端在较小的尺度。我们认为,在小尺度上的光度依赖的集群是一个必要的组成部分的星系晕占领模型的蓝色,恒星形成的星系,以及红色,淬火星系。

英文摘要:

We report small-scale clustering measurements from the PRIMUS spectroscopic redshift survey as a function of color and luminosity. We measure the real-space cross-correlations between 62,106 primary galaxies with PRIMUS redshifts and a tracer population of 545,000 photometric galaxies over redshifts from z=0.2 to z=1. We separately fit a power-law model in redshift and luminosity to each of three independent color-selected samples of galaxies. We report clustering amplitudes at fiducial values of z=0.5 and L=1.5 L*. The clustering of the red galaxies is ~3 times as strong as that of the blue galaxies and ~1.5 as strong as that of the green galaxies. We also find that the luminosity dependence of the clustering is strongly dependent on physical scale, with greater luminosity dependence being found between r=0.0625 Mpc/h and r=0.25 Mpc/h, compared to the r=0.5 Mpc/h to r=2 Mpc/h range. Moreover, over a range of two orders of magnitude in luminosity, a single power-law fit to the luminosity dependence is not sufficient to explain the increase in clustering at both the bright and faint ends at the smaller scales. We argue that luminosity-dependent clustering at small scales is a necessary component of galaxy-halo occupation models for blue, star-forming galaxies as well as for red, quenched galaxies.

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