We present a detailed study of Near-IR selected galaxies in a protocluster field at z = 3.13. Protocluster galaxies are selected using the available mutliwavelength data with the photometric redshift (photo-z) at 2.9 < z < 3.3, reaching a mass completeness of ~10^10 M_sun. Diverse types of galaxies have been found in the field including normal star-forming galaxies, quiescent galaxies and dusty star-forming galaxies. The photo-z galaxies form two large overdense structures in the field, largely overlapping with the previously identified galaxy overdensities traced by Ly{\alpha} emitters (LAEs) and Lyman break galaxies (LBGs) respectively. The northern overdensity consists of a large fraction of old and/or dusty galaxy populations, while the southern one is mainly composed of normal star-forming galaxies which are spatially correlated with the LAEs. This agrees with our previous study arguing the spatial offset of different galaxy overdensities may be due to halo assembly bias. Given the large end-to-end sizes of the two overdensities, one possibility is that they will form into a supercluster by the present day. We also find strong evidence that the star-formation activities of the galaxies in the overdense protocluster regions are enhanced in comparison to their field counterparts, which suggests an accelerated mass assembly in this protocluster.

中文翻译：

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对 z = 3.13 处原星系团中大质量星系的详细研究

我们详细研究了 z = 3.13 处原星系团场中的近红外选定星系。原星团星系是使用可用的多波长数据选择的，光度红移 (photo-z) 在 2.9 < z < 3.3，达到~10^10 M_sun 的质量完整性。在该领域已经发现了多种类型的星系，包括正常的恒星形成星系、静止星系和尘土飞扬的恒星形成星系。photo-z 星系在场中形成两个大的超密度结构，与先前确定的分别由 Ly{\alpha} 发射体（LAE）和莱曼断裂星系（LBG）追踪的星系超密度重叠。北方的超密度由大部分古老和/或尘土飞扬的星系群组成，而南部的主要由正常的恒星形成星系组成，这些星系在空间上与 LAE 相关。这与我们之前的研究一致，即不同星系密度的空间偏移可能是由于晕组装偏差。鉴于这两个超密度的端到端规模很大，一种可能性是它们将在今天形成一个超星系团。我们还发现强有力的证据表明，与现场对应的星系相比，高密度原星系团区域中星系的恒星形成活动增强，这表明该原星系团中的质量组装加速。一种可能性是，它们将在今天形成一个超级星系团。我们还发现强有力的证据表明，与现场对应的星系相比，高密度原星系团区域中星系的恒星形成活动增强，这表明该原星系团中的质量组装加速。一种可能性是，它们将在今天形成一个超级星系团。我们还发现强有力的证据表明，与现场对应的星系相比，高密度原星系团区域中星系的恒星形成活动增强，这表明该原星系团中的质量组装加速。