Baryon fractions in clusters of galaxies: evidence against a pre-heating model for entropy generation
Baryon fractions in clusters of galaxies: evidence against a pre-heating model for entropy generation
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DOI：
10.1111/j.1365-2966.2010.18165.x
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发表时间：
2010-07
影响因子：
4.8
通讯作者：
O. Young;P. Thomas;C. Short;F. Pearce
中科院分区：
文献类型：
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作者：
O. Young;P. Thomas;C. Short;F. Pearce
千年气体项目旨在进行千年模拟的光滑粒子流体动力学再模拟，提供数百个大质量星系团与x射线调查进行比较（170个星系团的kTsl > 3 keV）。本文用不同的物理加热机制对星团的热气体和恒星组分进行了模拟。这些方法无法重现冷核系统，但可以成功地匹配非冷核集群的热气体分布。虽然观测数据存在很大的离散性，但模拟的星团与r500范围内的综合气体馏分基本匹配。然而，与先前的工作一致，它们与恒星分数相比表现得不那么好，对星团质量的依赖比观测到的要弱得多。早期预热的模拟中，热气体分数随红移的演化比持续反馈的模拟大得多；观测结果支持后一种模式。热气体组分对星系团物理的强烈依赖限制了它作为宇宙参数探测的应用。
The Millennium Gas project aims to undertake smoothed-particle hydrodynamic resimulations of the Millennium Simulation, providing many hundred massive galaxy clusters for comparison with X-ray surveys (170 clusters with kTsl > 3 keV). This paper looks at the hot gas and stellar fractions of clusters in simulations with different physical heating mechanisms. These fail to reproduce cool-core systems but are successful in matching the hot gas profiles of non-cool-core clusters. Although there is immense scatter in the observational data, the simulated clusters broadly match the integrated gas fractions within r500 . In line with previous work, however, they fare much less well when compared to the stellar fractions, having a dependence on cluster mass that is much weaker than is observed. The evolution with redshift of the hot gas fraction is much larger in the simulation with early preheating than in one with continual feedback; observations favour the latter model. The strong dependence of hot gas fraction on cluster physics limits its use as a probe of cosmological parameters.