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arXiv 1310.2172astro-ph.CO
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WIRCam深度调查II:大规模选择聚类

The WIRCam Deep Survey II: Mass Selected Clustering

R. M. Bielby, V. Gonzalez-Perez, H. J. McCracken, O. Ilbert, E. Daddi, O. Le Fèvre, P. Hudelot, J. -P. Kneib, Y. Mellier, C. Willott

摘要:

本文利用WIRCam深度巡天(WIRDS)分析了从z ~ 2到现在的星系团。WIRDS将深层近红外数据与CFHTLS深层场的深层光学数据相结合,提供了2.4平方米有效区域的光度数据集。度,由此可以估计出精确的光度红移和恒星质量。我们使用的数据来计算角关联函数的星系样本分裂的恒星形成活动,恒星质量和红移。我们估计每个样本的实空间聚类,确定聚类长度和幂律斜率。对于质量不变的星系,我们发现成团尺度在z ~ 2之前没有演化。按质量分割星系样本,我们看到质量越大的星系在所有红移处的聚集尺度越大。我们用我们的结果检验了GALFORM半解析星系形成模型,发现两者是一致的。我们将星系群分为被动星系群和恒星形成星系群,发现被动星系群在所有红移处的聚集尺度都比质量小于$10^{11}M_\odot/h$的恒星形成星系群大得多,这表明即使在z ~ 2处,被动星系群也比大部分恒星形成星系群存在于更致密的环境中。对于恒星质量为$>10^{11}M_\odot/h$的恒星形成星系,我们发现在所有红移范围内的聚集强度约为8 Mpc/h,与被动人口的测量结果相当。此外,对于恒星形成的星系,我们看到,集群强度增加更高的恒星质量系统,但有一个被动星系的质量依赖的迹象很少。最后,我们研究了星系恒星质量和暗物质晕质量之间的联系,在WIRDS数据和GALFORM预测中两者之间存在明显的相关性。

英文摘要:

We present an analysis of the clustering of galaxies from z ~ 2 to the present day using the WIRCam Deep Survey (WIRDS). WIRDS combines deep near-infrared data with the deep optical data from the CFHTLS Deep fields, providing a photometric data-set over an effective area of 2.4 sq. deg., from which accurate photometric redshifts and stellar masses can be estimated. We use the data to calculate the angular correlation function for galaxy samples split by star-formation activity, stellar mass and redshift. We estimate the real-space clustering for each sample, determining clustering lengths and power-law slopes. For galaxies selected by constant mass, we find that the clustering scale shows no evolution up to z ~ 2. Splitting the galaxy sample by mass, we see that higher mass galaxies have larger clustering scales at all redshifts. We use our results to test the GALFORM semi-analytical galaxy formation model and find the two are consistent. We split the galaxy population into passive and star-forming populations and find that the passive galaxy population shows a significantly larger clustering scale at all redshifts than the star-forming population below masses of ~$10^{11}M_\odot/h$, showing that even at z ~ 2 passive galaxies exist in denser environments than the bulk of the star-forming galaxy population. For star-forming galaxies with stellar masses $>10^{11}M_\odot/h$, we find a clustering strength of ~8Mpc/h across all redshifts, comparable to the measurements for the passive population. Also, for star-forming galaxies we see that clustering strength increases for higher stellar mass systems, however there is little sign of a mass dependence in passive galaxies. Finally, we investigate the connection between galaxy stellar mass and dark matter halo mass, showing a clear correlation between the two in both the WIRDS data and the GALFORM predictions.

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