Turbulence in the Intracluster Medium
Turbulence in the Intracluster Medium
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DOI：
10.1007/978-3-662-44625-6_21
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
M. Brüggen;F. Vazza
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文献类型：
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作者：
M. Brüggen;F. Vazza
我们回顾了关于星系团内介质湍流的知识，星系团内介质是一种非常热的稀释等离子体，渗透到星系团中。彻底了解簇内介质中的湍流对于使用簇来确定宇宙学参数至关重要。此外，簇提供了一个独特的实验室来研究非常独特和极端的等离子体。回顾了观测证据以及（磁）流体动力学模拟的结果。特别是，我们评估了湍流的各种驱动因素的作用：吸积和合并、活动星系核、星系运动和传导不稳定性。研究表明，星系团中吸积驱动的湍流在内部区域主要是切向的，在接近维里半径的区域是各向同性的，而活动星系核主要以接近音速的速度驱动径向湍流运动。在星团尺度上，驱动湍流的能量主导机制是大型星团合并。在本章中，我们将重点关注大尺度上的湍流运动——微观物理湍流的特性在本书的其他地方进行了回顾（参见布鲁内蒂和琼斯的章节）。
We review our knowledge about turbulence in the intracluster medium, a very hot, dilute plasma that permeates clusters of galaxies. A thorough understanding of turbulence in the intracluster medium is crucial for the use of clusters to determine cosmological parameters. Moreover, clusters provide a unique laboratory to study a very unique and extreme plasma. Both, the observational evidence as well as results from (magneto-)hydrodynamical simulations are reviewed. In particular, we assess the roles of various drivers of turbulence: accretion and merging, active galactic nuclei, the motion of galaxies and conductive instabilities. It has been shown that the turbulence driven by accretion in galaxy clusters is mostly tangential in the inner regions and isotropic in regions close to the virial radius, while AGN drive mostly radial turbulent motions at close to sonic speeds. On the cluster scale, the energetically dominant mechanism for driving turbulence are major cluster mergers. In this chapter, we will focus on turbulent motions on the large scales—the properties of microphysical turbulence are reviewed elsewhere in this book (see the chapter by Brunetti and Jones).