The formation of a blue cluster in the local Universe

作     者：温庆新 罗煜 康熙 Qing-Xin Wen;Yu Luo;Xi Kang

作者机构：Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210033China School of Astronomy and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Zhejiang University-Purple Mountain Observatory Joint Research Center for AstronomyZhejiang UniversityHangzhou 310037China 

出 版 物：《Research in Astronomy and Astrophysics》 (天文和天体物理学研究（英文版）)

年 卷 期：2020年第20卷第12期

页      面：337-346页

核心收录：

学科分类：0709[理学-地质学] 07[理学] 0708[理学-地球物理学] 070401[理学-天体物理] 0704[理学-天文学] 0825[工学-航空宇航科学与技术] 

基　　金：funded by the 973 program(No.2015CB857003) the NSFC(Nos.11825303,11861131006,11333008 and 11703091)。 

主　　题：galaxies:clusters:statistical galaxies:evolution galaxies:formation galaxies:blue fraction 

摘      要：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 a high fraction of blue galaxies(∼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 the local Universe.In total,we find four blue clusters with halo mass ∼10^14 M⊙ at 0.02 z0.082,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.