The near-infrared luminosity function of cluster galaxies beyond redshift one
The near-infrared luminosity function of cluster galaxies beyond redshift one
复制标题
红移1以上星系团的近红外光度函数
DOI：
10.1051/0004-6361:20054341
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发表时间：
2006
影响因子：
6.5
通讯作者：
S. Toft
中科院分区：
文献类型：
--
作者：
V. Strazzullo;P. Rosati;S. Stanford;S. Stanford;C. Lidman;M. Nonino;R. Demarco;P. Eisenhardt;S. Ettori;V. Mainieri;S. Toft
目标。我们利用z = 1.11，1.24，1.27的三个X射线发光星系团的近红外图像，确定了红移z = 1.2的星系团星系的Ks波段光度函数（LF），并推导了相应的恒星质量函数。方法.通过统计背景扣除法，复合LF可以被推导到M +4，并且可以用Schechter函数很好地描述，其中K = 20.5 + 0.4 − 1，α = − 1.0 + 0.2 − 0.3。利用现有的X射线质量分布，我们确定了这三个集群的M/L比，这往往低于在本地宇宙中测量的。最后，从Ks波段合成LF导出了星系团的恒星质量函数。结果根据这些数据，在类似的红移下，团星系LF和场星系LF之间没有明显的差异。我们还发现，在明亮的地方，z = 1.2没有显著的变化（2。结论.这项工作中获得的结果支持并扩展了以前的发现，即明亮星系中的大多数恒星都是在高红移时形成的，并且KS明亮（M> 10 11 M）星系已经在z = 1.2的位置，至少在X射线发光星系团的中心区域。再加上最近关于场星系恒星质量函数的结果，这意味着大部分恒星质量已经在z1之前聚集在大质量星系中，无论是在低密度还是高密度环境中。
Aims. We determined the Ks band luminosity function (LF), and inferred the corresponding stellar mass function, of cluster galaxies at redshift z � 1.2, using near-infrared images of three X-ray luminous clusters at z = 1.11, 1.24, 1.27. Methods. The composite LF was derived down to M ∗ + 4, by means of statistical background subtraction, and is well described by a Schechter function with K ∗ = 20.5 +0.4 −1 and α = −1.0 +0.2 −0.3. Using available X-ray mass profiles we determined the M/L ratios of these three clusters, which tend to be lower than those measured in the local universe. Finally, from the Ks band composite LF we derived the stellar mass function of cluster galaxies. Results. With these data, no significant difference can be seen between the cluster galaxies LF and the LF of field galaxies at similar redshift. We also found no significant evolution out to z � 1.2 in the bright ( 2. Conclusions. The results obtained in this work support and extend previous findings that most of the stars in bright galaxies were formed at high redshift, and that Ks-bright (M > 10 11 M� ) galaxies were already in place at z � 1.2, at least in the central regions of X-ray luminous clusters. Together with recent results on the field galaxy stellar mass function, this implies that most of the stellar mass is already assembled in massive galaxies by z � 1, both in low and high density environments.