Spitzer/MIPS 24 μm Observations of Galaxy Clusters: An Increasing Fraction of Obscured Star-forming Members from z = 0.02 to z = 0.83
Spitzer/MIPS 24 μm Observations of Galaxy Clusters: An Increasing Fraction of Obscured Star-forming Members from z = 0.02 to z = 0.83
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DOI：
10.1086/592730
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发表时间：
2008-06
期刊：
影响因子：
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通讯作者：
A. Saintonge;K. Tran;B. Holden
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文献类型：
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作者：
A. Saintonge;K. Tran;B. Holden
我们研究了8个大质量（Mvir ≥ 5 × 1014 M）星系团中1315个经光谱确认的成员的中红外光谱性质，这些星系团的红移范围从0.02到0.83。所选的星系团都有斯皮策/MIPS 24 μm深观测，哈勃和地基测光，以及广泛的红移目录。我们第一次观察到，中红外星星形成率高于5百万年−1的星系团比例从z = 0.02时的3%增加到z = 0.83时的13%（RP = 1百万秒差距）。即使只考虑最大质量的成员（M * 1010 M），这种增加也是重现的。24 μm的观测结果显示，蓝色/恒星形成星系团的演化比颜色选择样本更强：有尘埃的，强烈的恒星形成星系团的数量随着红移而增加，将这些与光学定义的Butcher-Oemler成员[Δ（B − V）<-0.2]相结合，使星团内部Mpc中蓝色/恒星形成星系的总比例增加了一倍，达到约23%。z = 0.83。这些结果，我们的斯皮策/MIPS的第一个红星团巡天（SMIRCS），支持早期的研究表明，恒星形成成员的增加是由集群组装和星系的下落，正如预期的框架中的分层形成。
We study the mid-infrared properties of 1315 spectroscopically confirmed members in eight massive (Mvir≳ 5 × 1014 M☉) galaxy clusters covering the redshift range from 0.02 to 0.83. The selected clusters all have deep Spitzer/MIPS 24 μm observations, Hubble and ground-based photometry, and extensive redshift catalogs. We observe for the first time an increase in the fraction of cluster galaxies with mid-infrared star formation rates higher than 5 M☉ yr−1 from 3% at z = 0.02 to 13% at z = 0.83 (RP ⩽ 1 Mpc). This increase is reproduced even when considering only the most massive members (M* ⩾ 4 × 1010 M☉). The 24 μm observations reveal stronger evolution in the fraction of blue/star-forming cluster galaxies than in color-selected samples: the number of dusty, strongly star-forming cluster galaxies increases with redshift, and combining these with the optically defined Butcher-Oemler members [Δ (B − V) < − 0.2] doubles the total fraction of blue/star-forming galaxies in the inner Mpc of the clusters to ~23% at z = 0.83. These results, the first of our Spitzer/MIPS Infra-Red Cluster Survey (SMIRCS), support earlier studies indicating that the increase in star-forming members is driven by cluster assembly and galaxy infall, as is expected in the framework of hierarchical formation.