Accelerated Galaxy Growth and Environmental Quenching in a Protocluster at z = 3.24
Accelerated Galaxy Growth and Environmental Quenching in a Protocluster at z = 3.24
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DOI：
10.3847/1538-4357/abe62e
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发表时间：
2021-02
期刊：
影响因子：
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通讯作者：
Ke Shi;J. Toshikawa;Kyoung-soo Lee;Tao Wang;Z. Cai;T. Fang
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作者：
Ke Shi;J. Toshikawa;Kyoung-soo Lee;Tao Wang;Z. Cai;T. Fang
我们提出了一个多波长的研究星系D4 UD 01，光谱证实的原星系团在z = 3.24，调查环境的趋势。根据K-S波段的测光红移（photo-z）为3.0 < z < 3.4的观测结果，选取了450个星系，其中约12%的星系属于静止星系。静止星系是整个样本中质量最大、最红的星系之一。我们确定了一个大的photo-z星系在外地，这是接近以前光谱证实的来源的原星系团。我们发现，静止的星系主要集中在过密的原星系团区域具有较高的静止分数，显示出环境淬火的迹象。在恒星质量函数中，原星系团中的星系团形成的速度比它们的场对应物要快，这表明在过密区域有早期和加速的质量组装。虽然在原星团中发现了被抑制的星星形成的微弱证据，但统计数据还不足以得出明确的结论。我们的工作揭示了当宇宙只有2 Gyr时，大质量星系的形成是如何在原星系团的致密区域受到影响的。
We present a multiwavelength study of galaxies around D4UD01, a spectroscopically confirmed protocluster at z = 3.24, to investigate environmental trends. 450 galaxies are selected based on K S band detection with photometric redshifts (photo-z) at 3.0 < z < 3.4, among which ∼12% are classified as quiescent galaxies. The quiescent galaxies are among the most massive and reddest ones in the entire sample. We identify a large photo-z galaxy overdensity in the field, which lies close to the previously spectroscopically confirmed sources of the protocluster. We find that the quiescent galaxies are largely concentrated in the overdense protocluster region with a higher quiescent fraction, showing a sign of environmental quenching. Galaxies in the protocluster are forming faster than their field counterparts as seen in the stellar mass function, suggesting early and accelerated mass assembly in the overdense regions. Although weak evidence of suppressed star formation is found in the protocluster, the statistics are not significant enough to draw a definite conclusion. Our work sheds light on how the formation of massive galaxies is affected in the dense region of a protocluster when the universe was only 2 Gyr old.