Galaxies in clusters: the observational characteristics of bow shocks, wakes and tails
Galaxies in clusters: the observational characteristics of bow shocks, wakes and tails
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星系团中的星系：弓激波、尾流和尾部的观测特征
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
T. Ponman
中科院分区：
文献类型：
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作者：
I. Stevens;D. Acreman;T. Ponman
星系团中星系与星系团内介质(ICM)相互作用的动力学特征可能会产生关于星系团结构和动力学历史的重要信息。为了加深我们对这一现象的理解，我们提供了星系通过星系团时星系/ICM相互作用的数值模拟结果。对ICM温度(KT=1，4和8keV)的大范围进行了模拟，代表了从贫星团或群体到富星团的各种情况。在这些模拟中可以识别出几个动力学特征：对于超音速星系运动，存在领先的弓激波，以及星系后面的弱引力聚焦尾迹或尾巴(类似于Bondi-Hoyle吸积)。对于质量补充率更高、星际介质(ISM)密度更高的星系，主要特征是密集的冲压剥离尾巴。与其他模拟结果一致，我们发现ICM/Galaxy ISM相互作用可以导致复杂的依赖于时间的动力学，冲击压力剥离以一种插曲的方式发生。为了便于比较动力学研究和X射线观测的观测结果，我们根据这些模拟计算了合成X射线通量和硬度图。这些计算预测，撞击压力剥离的尾巴通常是最明显的特征，尽管在附近的星系中，在星系之前的弓激波在更深层次的X射线观测中也应该是明显的。我们简要讨论了这些结果，并与有证据表明存在这种相互作用的星系的X射线观测进行了比较。
The dynamical signatures of the interaction between galaxies in clusters and the intracluster medium (ICM) can potentially yield significant information about the structure and dynamical history of clusters. To develop our understanding of this phenomenon we present results from numerical modelling of the galaxy/ICM interaction, as the galaxy moves through the cluster. The simulations have been performed for a broad range, of ICM temperatures (kT = 1,4 and 8 keV), representative of poor clusters or groups through to rich clusters. There are several dynamical features that can be identified in these simulations; for supersonic galaxy motion, a leading bow-shock is present, and also a weak gravitationally focussed wake or tail behind the galaxy (analogous to Bondi-Hoyle accretion). For galaxies with higher mass-replenishment rates and a denser interstellar medium (ISM), the dominant feature is a dense ram-pressure stripped tail. In line with other simulations, we find that the ICM/galaxy ISM interaction can result in complex time- dependent dynamics, with ram-pressure stripping occurring in an episodic manner. In order to facilitate this comparison between the observational consequences of dynamical studies and X-ray observations we have calculated synthetic X-ray flux and hardness maps from these simulations. These calculations predict that the ram-pressure stripped tail will usually be the most visible feature, though in nearby galaxies the bow-shock preceding the galaxy should also be apparent in deeper X-ray observations. We briefly discuss these results and compare with X-ray observations of galaxies where there is evidence of such interactions.