论文标题
本地宇宙中蓝色簇的形成
The formation of blue cluster in local Universe
论文作者
论文摘要
从屠夫 - oemler效应中众所周知，密集环境中的星系大多是红色的，恒星形成很小，而星系组/簇中的蓝色星系的比例也随着红移而迅速下降。 Hashimoto等人的最新工作。报道了一个局部的“蓝色集群”，其蓝色星系高（$ \ sim 0.57 $），高于模型预测。他们将这个蓝色簇归因于沿簇周围的丝状结构的气体喂养。在这项工作中，我们使用Sloan Digital Sky Survey Data Release 7（SDSS DR7）和半分析模型（SAM）的组目录来研究本地宇宙中蓝色簇的形成。总的来说，我们发现四个带有光晕质量$ \ sim 10^{14} m _ {\ odot} $的蓝色簇为$ 0.02 <z <0.082 $，而仅Hashimoto等人发现了一个。处于丝状结构。 SAM预测，蓝色簇的形成时间稍后，并且大多数蓝色卫星星系最近被积聚。我们得出的结论是，蓝色簇的形成主要由新成立的蓝色卫星支配，而不是大规模环境的影响。
It is well known from the Butcher-Oemler effect that galaxies in dense environment are mostly red with little star formation and the fraction of blue galaxies in galaxy groups/clusters also declines rapidly with redshifts. A recent work by Hashimoto et al. reported a local 'blue cluster' with high fraction of blue galaxies ($\sim 0.57$), higher than the model predictions. They ascribed this blue cluster to the feeding of gas along a filamentary structure around the cluster. In this work we use group catalog from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7) and the state-of-art of semi-analytic model (SAM) to investigate the formation of blue clusters in local Universe. In total, we find four blue clusters with halo mass $\sim 10^{14}M_{\odot}$ at $0.02 < z < 0.082$, while only the one found by Hashimoto et al. is in a filamentary structure. The SAM predicts that blue clusters have later formation time and most blue satellite galaxies are recently accreted. We conclude that the formation of blue clusters is mainly governed by newly accreted blue satellites, rather than the effect of large-scale environment.
