Probing the dynamical state, baryon content, and multiphase nature of galaxy clusters with bright background QSOs
Probing the dynamical state, baryon content, and multiphase nature of galaxy clusters with bright background QSOs
复制标题
利用亮背景 QSO 探测星系团的动力学状态、重子含量和多相性质
DOI：
10.1093/mnras/sty2492
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发表时间：
2018
影响因子：
4.8
通讯作者：
Li Ji
中科院分区：
文献类型：
--
作者：
Chong Ge;Q Daniel Wang;Joseph N Burchett;Todd M Tripp;Ming Sun;Zhiyuan Li;Qiusheng Gu;Li Ji
我们启动了一项计划，利用背景 QSO 的 X 射线成像和紫外吸收线光谱来研究星系团中气体的物理/动力学状态以及星系团环境对各个星系气态晕的影响。在这里，我们报告了对具有此类 QSO 的五个星系团的钱德拉和 XMM-牛顿档案数据进行分析的结果，其中一个星系团具有档案紫外线光谱。我们描述了这些星团的引力质量和动力学状态，以及热星团内介质（ICM）特性。大多数星团是基于X射线形态参数、X射线温度分布、X射线峰值与最亮星团星系（BCG）之间的大偏移的动态扰动星团。根据标准宇宙学，$r_{500}$ 内这些星团的热 ICM 和恒星中的重子含量低于引力质量的预期值。我们还估计了沿朝向背景 QSO 的视线的热 ICM 的柱密度，并利用现有的 UV 观测对单视线的暖热相设置了上限。这些柱密度与用紫外吸收线光谱法测量的温热和温热 ICM 的柱密度相比，将使我们能够探究各种气相之间的关系及其与团簇的加热/冷却和动力学过程的关系。此外，我们对探测一个星团的档案 QSO 光谱的分析强调了高质量、有针对性的 UV 观测的需要，以强有力地限制 10$^{5-6}$ K 气相。
We have initiated a programme to study the physical/dynamical state of gas in galaxy clusters and the impact of the cluster environment on gaseous halos of individual galaxies using X-ray imaging and UV absorption line spectroscopy of background QSOs. Here we report results from the analysis Chandra and XMM-Newton archival data of five galaxy clusters with such QSOs, one of which has an archival UV spectrum. We characterize the gravitational masses and dynamical states, as well as the hot intracluster medium (ICM) properties of these clusters. Most clusters are dynamically disturbed clusters based on the X-ray morphology parameters, the X-ray temperature profiles, the large offset between X-ray peak and brightest cluster galaxy (BCG). The baryon contents in the hot ICM and stars of these clusters within $r_{500}$ are lower than the values expected from the gravitational masses, according to the standard cosmology. We also estimate column densities of the hot ICM along the sightlines toward the background QSOs as well as place upper limits on the warm-hot phase for the one sightline with existing UV observations. These column densities, compared with those of the warm and warm-hot ICM to be measured with UV absorption line spectroscopy, will enable us to probe the relationship among various gaseous phases and their connection to the heating/cooling and dynamical processes of the clusters. Furthermore, our analysis of the archival QSO spectrum probing one cluster underscores the need for high quality, targeted UV observations to robustly constrain the 10$^{5-6}$ K gas phase.