论文标题
最明亮的簇星系：中心可以（不？）保持
Brightest Cluster Galaxies: the centre can(not?) hold
论文作者
论文摘要
我们探讨了最明亮的星系星系（BCG）与当地环境的一致性的持久性。我们发现，BCG的很大一部分与X射线气体分布的质心和/或显示出特殊的速度不一致（相对于簇平均值，它们不在静止状态）。尽管如此，我们发现BCG通常与群集质量分布保持一致，即使它们具有从X射线中心和明显的特殊速度的显着偏移。大偏移与简单的理论模型不一致。为了解释这些观察结果，BCG必须沿其主要轴（主要的插入方向）优先进行合并。这种BCG在被合并或碰撞移位后可能会在聚类潜力中振荡，或者暗物质光环本身可能尚未放松。
We explore the persistence of the alignment of brightest cluster galaxies (BCGs) with their local environment. We find that a significant fraction of BCGs do not coincide with the centroid of the X-ray gas distribution and/or show peculiar velocities (they are not at rest with respect to the cluster mean). Despite this, we find that BCGs are generally aligned with the cluster mass distribution even when they have significant offsets from the X-ray centre and significant peculiar velocities. The large offsets are not consistent with simple theoretical models. To account for these observations BCGs must undergo mergers preferentially along their major axis, the main infall direction. Such BCGs may be oscillating within the cluster potential after having been displaced by mergers or collisions, or the dark matter halo itself may not yet be relaxed.
