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arXiv 1105.2826astro-ph.CO
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团内气压、熵注入与红移演化

Intracluster gas pressure, entropy injection and redshift evolution

Biman B. Nath, Subhabrata Majumdar

摘要:

根据最近观测到的团内介质(ICM)的普遍压力剖面,我们研究了ICM中熵注入的效应。从一个幂律熵的配置文件,预计在没有任何反馈,我们表明,一个简单的通用处方的熵注入结果在最终的,观察到的普遍的压力分布。这个简单的处方有两个组成部分,一个与熵的整体增加有关,另一个与集群中心部分的注入有关。重要的是,熵注入的两个分量都需要产生最终的通用压力分布。这表明既需要预热ICM,也需要{ \it原位} AGN/SNe加热。我们证明了该方法的实用性,通过扩展计算集群在高红移,并预测红移演化的集群标度关系,可以对数据进行测试。我们表明,自相似演化的普遍压力分布是相当于一个负的熵注入红移的演化,与缩放$S_{inj} \propto (1+z)^{-0.8} S_{inj}(z=0)$。我们还表明,目前的观测数据表明,熵注入减少红移。

英文摘要:

We study the effect of entropy injection in the intracluster medium (ICM) in light of the recent observationally determined universal pressure profile of the ICM. Beginning with a power-law entropy profile that is expected in the absence of any feedback, we show that a simple universal prescription of entropy injection results in the final, observed universal pressure profile. This simple prescription has two components, one associated with an overall increase in entropy and another associated with injection in the central parts of the cluster. Importantly, both the components of entropy injection are needed to produce the final universal pressure profile. This is indicative of a need of both preheating the ICM as well {\it in situ} AGN/SNe heating. We demonstrate the usefulness of the method by extending the calculations to clusters at high redshift, and predict redshift evolution of cluster scaling relations that can be tested against data. We show that the self-similar evolution of the universal pressure profile is equivalent to a negative evolution of entropy injection with redshift, with a scaling $S_{inj} \propto (1+z)^{-0.8} S_{inj}(z=0)$. We also show the current observational data are indicative of the entropy injection decreasing with redshift.

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