GALAXY CLUSTERS AT HIGH REDSHIFT AND EVOLUTION OF BRIGHTEST CLUSTER GALAXIES
GALAXY CLUSTERS AT HIGH REDSHIFT AND EVOLUTION OF BRIGHTEST CLUSTER GALAXIES
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DOI：
10.1088/0004-637x/734/1/68
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发表时间：
2011-04
期刊：
影响因子：
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通讯作者：
Z. Wen;J. Han
中科院分区：
文献类型：
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作者：
Z. Wen;J. Han
高红移星系团的识别对于宇宙学和星系团演化的研究具有重要意义。利用星系的光度学红移，我们从加拿大-法国-夏威夷望远镜(CFHT)宽场识别出631个星系团，从CFHT深场识别出202个星系团，从宇宙演化调查(COSMOS)场识别出187个星系团，从斯皮策广域红外星系外探测(SWIRE)场识别出737个星系团。这些团簇的红移在0.1≲z≲1.6的范围内。合并这些集群样本，在四个调查区得到1644个集群，其中1088个是新发现的，超过一半来自大型太古油田。在z⩾1的2 2 8个星团中，有191个是新发现的，其中大部分来自太空场。利用这个大样本的高红移星系团，我们研究了最亮星系团(BCG)的颜色演化。BCG的r‘−z’和r+−m3.6μm颜色符合恒星群合成模型，即BCG是在红移ZF⩾2处形成的被动演化的。红移z>；0.8时BCG的g‘−z’和B−m3.6μm颜色系统地比ZF∼2形成的星系的被动演化模型更蓝，这表明恒星是在高红移的BCG中形成的。
Identification of high-redshift clusters is important for studies of cosmology and cluster evolution. Using photometric redshifts of galaxies, we identify 631 clusters from the Canada–France–Hawaii Telescope (CFHT) wide field, 202 clusters from the CFHT deep field, 187 clusters from the Cosmic Evolution Survey (COSMOS) field, and 737 clusters from the Spitzer Wide-area InfraRed Extragalactic Survey (SWIRE) field. The redshifts of these clusters are in the range 0.1 ≲ z ≲ 1.6. Merging these cluster samples gives 1644 clusters in the four survey fields, of which 1088 are newly identified and more than half are from the large SWIRE field. Among 228 clusters of z ⩾ 1, 191 clusters are newly identified, and most of them from the SWIRE field. With this large sample of high-redshift clusters, we study the color evolution of the brightest cluster galaxies (BCGs). The r′ − z′ and r+ − m3.6 μm colors of the BCGs are consistent with a stellar population synthesis model in which the BCGs are formed at redshift zf ⩾ 2 and evolved passively. The g′ − z′ and B − m3.6 μm colors of the BCGs at redshifts z > 0.8 are systematically bluer than the passive evolution model for galaxies formed at zf ∼ 2, indicating star formation in high-redshift BCGs.