Galaxy populations in the most distant SPT-SZ clusters
Galaxy populations in the most distant SPT-SZ clusters
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DOI：
10.1051/0004-6361/201833944
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发表时间：
2018-07
影响因子：
6.5
通讯作者：
V. Strazzullo;M. Pannella;J. Mohr;A. Saro;M. Ashby;M. Bayliss;S. Bocquet;E. Bulbul;G. Khullar-G.-Khul
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文献类型：
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作者：
V. Strazzullo;M. Pannella;J. Mohr;A. Saro;M. Ashby;M. Bayliss;S. Bocquet;E. Bulbul;G. Khullar-G.-Khul
我们展示了在 2500 deg2 南极望远镜 Sunyaev Zel'dovich 效应 (SPT-SZ) 调查中发现的最高红移星系团中的星系群研究的第一个结果，该星系团对从 z ∼ 0.2 到存在此类巨大结构的最高红移的 M500 ≳ 3 × 1014 M⊙ 星系团敏感。星团选择是一阶独立于星系属性的，使得 SPT-SZ 样本特别适合星团星系种群研究。我们使用哈勃和斯皮策太空望远镜对五个 z ≳ 1.4、S/NSZE > 5 星团进行了四波段成像活动，这些星团是此次红移中已知的最罕见的最大星团之一。所有五个星团都显示出明显的红色星系密度过高，其颜色与最初的星团红移估计一致，尽管其中一个星团（SPT-CLJ0607-4448）显示出的星系集中度远不如其他星团那么突出。该样本中红移最高的星团是 z ∼ 1.72 处的 SPT-CLJ0459–4947，是迄今为止通过其星团内介质发现的距离最远的 M500 > 1014 M⊙ 星团，并且是该质量范围内 z ≳ 1.7 处仅有的三个已知星团之一，无论选择如何。基于静止星系和恒星形成星系的类UVJ光度分类，我们发现星团中心区域的静止分数（r/r500 10.85）。我们探索了恒星形成的发射对样本选择的影响，得出的结论是，这里研究的所有五个星团仍然会被检测到S/NSZE > 5，即使它们具有与现场测量相同的静止分数。因此，我们的结果表明可以有效抑制恒星形成最大质量星团的中心区域，早于 z ∼ 1.5 出现。
We present the first results from a galaxy population study in the highest redshift galaxy clusters identified in the 2500 deg2 South Pole Telescope Sunyaev Zel’dovich effect (SPT-SZ) survey, which is sensitive to M500 ≳ 3 × 1014 M⊙ clusters from z ∼ 0.2 out to the highest redshifts where such massive structures exist. The cluster selection is to first order independent of galaxy properties, making the SPT-SZ sample particularly well suited for cluster galaxy population studies. We carried out a four-band imaging campaign with the Hubble and Spitzer Space Telescopes of the five z ≳ 1.4, S/NSZE > 5 clusters, that are among the rarest most massive clusters known at this redshift. All five clusters show clear overdensities of red galaxies whose colors agree with the initial cluster redshift estimates, although one (SPT-CLJ0607–4448) shows a galaxy concentration much less prominent than the others. The highest redshift cluster in this sample, SPT-CLJ0459–4947 at z ∼ 1.72, is the most distant M500 > 1014 M⊙ cluster discovered thus far through its intracluster medium, and is one of only three known clusters in this mass range at z ≳ 1.7, regardless of selection. Based on UVJ-like photometric classification of quiescent and star-forming galaxies, we find that the quiescent fraction in the cluster central regions (r/r500 10.85. We have explored the impact of emission from star formation on the selection of this sample, concluding that all five clusters studied here would still have been detected with S/NSZE> 5, even if they had the same quiescent fraction as measured in the field. Our results thus point towards an efficient suppression of star formation in the central regions of the most massive clusters, occurring already earlier than z ∼ 1.5.