GALAXY CLUSTERS AT THE EDGE: TEMPERATURE, ENTROPY, AND GAS DYNAMICS NEAR THE VIRIAL RADIUS
GALAXY CLUSTERS AT THE EDGE: TEMPERATURE, ENTROPY, AND GAS DYNAMICS NEAR THE VIRIAL RADIUS
复制标题
边缘的星系团：维里半径附近的温度、熵和气体动力学
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
B. O’Shea
中科院分区：
文献类型：
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作者：
J. Burns;S. Skillman;B. O’Shea
最近，朱雀已经为大约维里半径的多个星系团生成了温度和熵剖面，以及气体密度、气体分数和质量剖面。在本文中，我们将这些新颖的 X 射线观测结果与使用 Enzo 代码的 N 体 + 流体动力学自适应网格细化宇宙学模拟的结果进行比较。模拟体积中 24 个基本无子结构的大质量星团样本与观测到的星团在温度、密度和熵分布方面具有极好的一致性。这支持了我们之前的论点，即星团具有“通用”的外部温度分布。此外，恩佐模拟中使用的最简单的绝热气体物理学似乎足以对这些星团的外部区域进行建模，而无需其他机制（例如非重力加热、冷却、磁场或宇宙射线）。然而，这些簇的外围并不处于流体静力平衡。在由细丝吸积产生的外部簇内介质中存在显着的整体流动和湍流。因此，气体没有完全受到热压力的支持。讨论了 X 射线数据质量估计的含义。
Recently, Suzaku has produced temperature and entropy profiles, along with profiles of gas density, gas fraction, and mass, for multiple galaxy clusters out to approximately the virial radius. In this paper, we compare these novel X-ray observations with results from N-body + hydrodynamic adaptive mesh refinement cosmological simulations using the Enzo code. There is excellent agreement in the temperature, density, and entropy profiles between a sample of 24 mostly substructure-free massive clusters in the simulated volume and the observed clusters. This supports our previous contention that clusters have “universal” outer temperature profiles. Furthermore, it appears that the simplest adiabatic gas physics used in these Enzo simulations is adequate to model the outer regions of these clusters without other mechanisms (e.g., non-gravitational heating, cooling, magnetic fields, or cosmic rays). However, the outskirts of these clusters are not in hydrostatic equilibrium. There is significant bulk flow and turbulence in the outer intracluster medium created by accretion from filaments. Thus, the gas is not fully supported by thermal pressure. The implications for mass estimation from X-ray data are discussed.