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arXiv 1111.6189astro-ph.CO
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Abell 1835到R_{200}的X射线、透镜和Sunyaev Zel'dovich三轴分析

X-ray, lensing and Sunyaev Zel'dovich triaxial analysis of Abell 1835 out to R_{200}

Andrea Morandi, Marceau Limousin, Jack Sayers, Sunil R. Golwala, Nicole G. Czakon, Elena Pierpaoli, Eric Jullo, Johan Richard, Silvia Ameglio

摘要:

测量星系团中暗物质(DM)和团内气体(IC)的内在形状和方向对于限制它们的形成和演化以及增强星系团作为更精确的宇宙学探针的使用至关重要。本文利用X射线、强透镜(SL)和Sunyaev Zel'dovich(SZ)观测资料,首次对Abell 1835星系团进行了三轴联合分析。我们参数化地重建DM和IC气体的全三维结构(三轴形状和主轴取向),以及IC气体的非热压力水平。我们发现DM的中长轴比和短长轴比分别为0.71 ± 0.08和0.59 ± 0.05,DM晕的长轴相对于视线倾斜18.3 ± 5.2 °。我们提出了第一个观测测量的非热压力出R_{200},这已被评估为几个百分比的总能量预算的内部区域,而达到约20%的外部体积。我们讨论了我们的方法的CDM方案的可行性的影响,专注于浓度参数C和DM伽马的内斜率,以测试冷暗物质(CDM)的结构形成的范例:我们测量伽马=1.01+/-0.06和C=4.32+/-0.44,接近CDM模型的预测值。结合X射线/SL数据在高空间分辨率,能够解决集群核心,与SZ数据,这是更敏感的集群外部体积,使我们能够表征的水平和梯度的气体熵分布和非热压力出R_{200},打破了退化的物理模型描述的ICM的热历史。

英文摘要:

Measuring the intrinsic shape and orientation of dark matter (DM) and intracluster (IC) gas in galaxy clusters is crucial to constraining their formation and evolution, and for enhancing the use of clusters as more precise cosmological probes. Extending our previous works, we present for the first time results from a triaxial joint analysis of the galaxy cluster Abell 1835, by means of X-ray, strong lensing (SL) and Sunyaev Zel'dovich (SZ) data. We parametrically reconstruct the full three-dimensional structure (triaxial shape and principal axis orientation) of both the DM and the IC gas, and the level of non-thermal pressure of the IC gas. We find that the intermediate-major and minor-major axis ratios of the DM are 0.71+/-0.08 and 0.59+/-0.05, respectively, and the major axis of the DM halo is inclined with respect to the line of sight at 18.3+/-5.2 deg. We present the first observational measurement of the non-thermal pressure out to R_{200}, which has been evaluated to be a few percent of the total energy budget in the internal regions, while reaching approximately 20% in the outer volumes. We discuss the implications of our method for the viability of the CDM scenario, focusing on the concentration parameter C and the inner slope of the DM gamma in order to test the cold dark matter (CDM) paradigm for structure formation: we measure gamma=1.01+/-0.06 and C=4.32+/-0.44, values which are close to the predictions of the CDM model. The combination of X-ray/SL data at high spatial resolution, capable of resolving the cluster core, with the SZ data, which are more sensitive to the cluster outer volume, allows us to characterize the level and the gradient of the gas entropy distribution and non-thermal pressure out to R_{200}, breaking the degeneracy among the physical models describing the thermal history of the ICM.

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