Galaxy groups are more than an intermediate scale between clusters and halos hosting individual galaxies, they are crucial laboratories capable of testing a range of astrophysics from how galaxies form and evolve to large scale structure (LSS) statistics for cosmology. Cosmological hydrodynamic simulations of groups on various scales offer an unparalleled testing ground for astrophysical theories. Widely used cosmological simulations with ∼(100 Mpc)${}^3$ volumes contain statistical samples of groups that provide important tests of galaxy evolution influenced by environmental processes. Larger volumes capable of reproducing LSS while following the redistribution of baryons by cooling and feedback are the essential tools necessary to constrain cosmological parameters. Higher resolution simulations can currently model satellite interactions, the processing of cool ($T\approx {10}^{4-5}$ K) multi-phase gas, and non-thermal physics including turbulence, magnetic fields and cosmic ray transport. We review simulation results regarding the gas and stellar contents of groups, cooling flows and the relation to the central galaxy, the formation and processing of multi-phase gas, satellite interactions with the intragroup medium, and the impact of groups for cosmological parameter estimation. Cosmological simulations provide evolutionarily consistent predictions of these observationally difficult-to-define objects, and have untapped potential to accurately model their gaseous, stellar and dark matter distributions.

中文翻译：

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模拟群和群内介质：星系团和星系之间令人惊讶的复杂和丰富的中间地带

星系群不仅仅是包含单个星系的星团和晕之间的中间尺度，它们是能够测试从星系如何形成和演化到宇宙学的大尺度结构 (LSS) 统计的一系列天体物理学的重要实验室。不同尺度的群体的宇宙学流体动力学模拟为天体物理学理论提供了无与伦比的试验场。使用 ∼(100 Mpc) 的广泛使用的宇宙学模拟${}^3$卷包含群体的统计样本，这些样本提供了受环境过程影响的星系演化的重要测试。能够在通过冷却和反馈跟踪重子重新分布的同时再现 LSS 的更大体积是约束宇宙学参数所必需的基本工具。更高分辨率的模拟目前可以模拟卫星相互作用，处理很酷（$吨\approx {10}^{4-5}$K) 多相气体和非热物理，包括湍流、磁场和宇宙射线传输。我们回顾了关于群的气体和恒星含量、冷却流和与中央星系的关系、多相气体的形成和处理、卫星与群内介质的相互作用以及群对宇宙学参数估计的影响的模拟结果。宇宙学模拟为这些观测上难以定义的物体提供了进化上一致的预测，并且具有未开发的潜力来准确模拟它们的气态、恒星和暗物质分布。