论文标题

核心和郊外星系簇中的凸起和磁盘的颜色

The colors of bulges and disks in the core and outskirts of galaxy clusters

论文作者

Barsanti, S., Owers, M. S., McDermid, R. M., Bekki, K., Bryant, J. J., Croom, S. M., Oh, S., Robotham, A. S. G., Scott, N., van de Sande, J.

论文摘要

环境在S0星系形成中的作用仍然不太了解,特别是在星系群的郊区。我们研究八个低红移簇,分析星系成员以群集为中心的距离$ \ sim2.5 \,r_ {200} $。我们在$ g $ - ,$ r $ - 和$ i $ bands中执行2D光度凸出 - 磁盘分解,我们可以从中确定469个双重组件星系。我们分别分析凸起和磁盘的颜色及其对预测的以群集为中心的距离以及当地星系密度的依赖性。对于我们的群集S0星系样本,我们发现凸起比周围的磁盘变红,显示出明显的颜色磁性趋势,并且具有与环境指标无关的颜色。另一方面,与我们的群集S0相关的磁盘随着以群集为中心的半径增加变得明显蓝色,但没有显示出色彩障碍关系的证据。磁盘颜色 - 拉迪乌斯关系主要由群集核心的星系驱动,$ 0 \ leq r/ r_ {200} <0.5 $。在投影相空间中,后挡板和插入星系的磁盘颜色没有显着差异。超过$ r_ {200} $,磁盘颜色不会随着本地星系密度而变化,这表明双组分星系的颜色不受预处理的影响。对于$ r_ {200} $的单个磁盘主导的星系,观察到了显着的颜色密度关系。我们得出的结论是,集群S0星系的形成主要是由作用在磁盘上的集群核心过程驱动的,而对于单组分磁盘为主的星系,发现了预处理的证据。 我们将公开释放凸出盘分解的数据。

The role of the environment on the formation of S0 galaxies is still not well understood, specifically in the outskirts of galaxy clusters. We study eight low-redshift clusters, analyzing galaxy members up to cluster-centric distances $\sim2.5\,R_{200}$. We perform 2D photometric bulge-disk decomposition in the $g$-, $r$- and $i$-bands from which we identify 469 double-component galaxies. We analyze separately the colors of the bulges and the disks and their dependence on the projected cluster-centric distance and on the local galaxy density. For our sample of cluster S0 galaxies, we find that bulges are redder than their surrounding disks, show a significant color-magnitude trend, and have colors that do not correlate with environment metrics. On the other hand, the disks associated with our cluster S0s become significantly bluer with increasing cluster-centric radius, but show no evidence for a color-magnitude relation. The disk color-radius relation is mainly driven by galaxies in the cluster core at $0\leq R/ R_{200}<0.5$. No significant difference is found for the disk colors of backsplash and infalling galaxies in the projected phase space. Beyond $R_{200}$, the disk colors do not change with the local galaxy density, indicating that the colors of double-component galaxies are not affected by pre-processing. A significant color-density relation is observed for single-component disk-dominated galaxies beyond $R_{200}$. We conclude that the formation of cluster S0 galaxies is primarily driven by cluster core processes acting on the disks, while evidence of pre-processing is found for single-component disk-dominated galaxies. We publicly release the data from the bulge-disk decomposition.

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