Witnessing the Hierarchical Assembly of the Brightest Cluster Galaxy in a Cluster at z = 1.26
Witnessing the Hierarchical Assembly of the Brightest Cluster Galaxy in a Cluster at z = 1.26
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见证 z = 1.26 处星团中最亮星团星系的分层组装
DOI：
10.1086/344400
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
R. de Propris
中科院分区：
文献类型：
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作者：
T. Yamada;Yohei Koyama;F. Nakata;M. Kajisawa;I. Tanaka;T. Kodama;S. Okamura;R. de Propris
我们获得了富X射线星系团RX J0848.9+4452中心区域z = 1.26的高分辨率K′带新图像。我们发现星团中最亮的星团星系（BCG）被清楚地分成两个不同的物体。而光学近红外颜色的对象是一致的被动演化模型的预测形成的星系在高红移，这两个星系的光度都是相当微弱的比预测的被动演化的BCGs在低和中等的红移集群。我们认为，这是一个正在进行的合并的正常集群椭圆星系形成的核心RX J0848.9+4452的主导星系的证据。这两个星系似乎指向附近的星系团ClG J0848+4453，并与其母星系团的外部X射线轮廓对齐，支持BCG形成的模型，该模型是通过沿沿着大尺度结构的准直下落形成的。
We have obtained a new high-resolution K′-band image of the central region of the rich X-ray cluster RX J0848.9+4452 at z = 1.26. We found that the brightest cluster galaxy (BCG) in the cluster is clearly separated into two distinct objects. Whereas the optical to near-infrared colors of the objects are consistent with the predictions of passive evolution models for galaxies formed at high redshift, the luminosities of the two galaxies are both considerably fainter than predicted by passive evolution of BCGs in low- and intermediate-redshift clusters. We argue that this is evidence of an ongoing merger of normal cluster elliptical galaxies to form the dominant galaxy in the core of RX J0848.9+4452. The two galaxies appear to point toward the nearby cluster ClG J0848+4453 and are aligned with the outer X-ray contour of their parent cluster, supporting a model of BCG formation by collimated infall along the surrounding large-scale structure.