Formation of Galaxy Clusters
Formation of Galaxy Clusters
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DOI：
10.1146/annurev-astro-081811-125502
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发表时间：
2012-05
影响因子：
33.3
通讯作者：
A. Kravtsov;S. Borgani
中科院分区：
文献类型：
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作者：
A. Kravtsov;S. Borgani
星系团的形成对应于初始密度场中最大的引力束缚过密度的坍缩，伴随着大爆炸以来最具能量的现象，以及引力诱导的坍缩动力学和与星系形成相关的重子过程之间的复杂相互作用。因此，星系团处于宇宙学和天体物理学的交叉路口，是检验引力结构形成、星系演化、星系际介质热力学和等离子体物理学模型的独特实验室。与此同时，它们的大质量使它们成为宇宙学时间内结构生长的有用探针，从而提供了与其他探针互补的宇宙学约束。在这篇综述中，我们描述了我们目前的理解集群的形成：从一般的图片崩溃从初始密度波动在不断膨胀的宇宙，以详细的模拟集群的形成，包括星系形成的影响。我们概述了两个领域中，可以获得高度准确的预测的理论模型和预测是不确定的，由于不确定的物理星系的形成和反馈的领域。前者包括暗物质晕托管集群的结构特性的描述，它们的质量函数，和集群特性。他们的研究为星系团的宇宙学应用和检验结构形成标准模型的基本假设提供了基础。后者包括对总气体和恒星组分的描述，以及团内等离子体的热力学和非热力学过程。他们的研究是星系形成模型和等离子体物理学的试验场。在这种情况下，我们确定了一个合适的径向范围内观察到的热性质的集群内等离子体表现出最有规律的行为，因此，可以用来定义强大的观测代理的总集群质量。最后，我们讨论了在非标准的宇宙模型，如非高斯模型的初始密度场和模型与修改的重力，沿着与前景，在不久的将来测试这些替代方案与大型集群调查的集群的形成。
Formation of galaxy clusters corresponds to the collapse of the largest gravitationally bound overdensities in the initial density field and is accompanied by the most energetic phenomena since the Big Bang and by the complex interplay between gravity-induced dynamics of collapse and baryonic processes associated with galaxy formation. Galaxy clusters are, thus, at the cross-roads of cosmology and astrophysics and are unique laboratories for testing models of gravitational structure formation, galaxy evolution, thermodynamics of the intergalactic medium, and plasma physics. At the same time, their large masses make them a useful probe of growth of structure over cosmological time, thus providing cosmological constraints that are complementary to other probes. In this review, we describe our current understanding of cluster formation: from the general picture of collapse from initial density fluctuations in an expanding Universe to detailed simulations of cluster formation including the effects of galaxy formation. We outline both the areas in which highly accurate predictions of theoretical models can be obtained and areas where predictions are uncertain due to uncertain physics of galaxy formation and feedback. The former includes the description of the structural properties of the dark matter halos hosting clusters, their mass function, and clustering properties. Their study provides a foundation for cosmological applications of clusters and for testing the fundamental assumptions of the standard model of structure formation. The latter includes the description of the total gas and stellar fractions and the thermodynamical and nonthermal processes in the intracluster plasma. Their study serves as a testing ground for galaxy formation models and plasma physics. In this context, we identify a suitable radial range where the observed thermal properties of the intracluster plasma exhibit the most regular behavior and, thus, can be used to define robust observational proxies for the total cluster mass. Finally, we discuss the formation of clusters in nonstandard cosmological models, such as non-Gaussian models for the initial density field and models with modified gravity, along with prospects for testing these alternative scenarios with large cluster surveys in the near future.