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arXiv 0802.3716astro-ph
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Wilkinson微波各向异性探测器(WMAP)3年数据中星系团电子压力剖面的测量

Measurement of the electron-pressure profile of galaxy clusters in Wilkinson Microwave Anisotropy Probe (WMAP) 3-year data

F. Atrio-Barandela, A. Kashlinsky, D. Kocevski, H. Ebeling

摘要:

使用WMAP 3年的数据,在接近$\sim 700$ X射线选定的集群的位置,我们已经检测到的热Sunyaev-Zeldovich(TSZ)效应的幅度在15 $σ$水平,迄今为止报道的最高统计意义。由于我们的集群样本的大尺寸,我们能够检测到相应的CMB扭曲到大集群中心半径。在其上检测到TSZ信号的区域在半径上平均比X射线发射区域大四倍,延伸到$\sim 3h_{70}^{-1}$ Mpc。我们发现,等温$β$模型不适合在大半径的电子压力,相反,重子的配置文件是一致的Navarro-Frenk-White配置文件,预计暗物质的一致性$Λ$ CDM模型。在簇的维里半径处的X射线温度从中心值下降一个因子$\sim 3-4$,取决于簇浓度参数。我们的研究结果表明,在大半径的集群动力学是由暗物质和牛顿引力很好地描述。

英文摘要:

Using WMAP 3-year data at the locations of close to $\sim 700$ X-ray selected clusters we have detected the amplitude of the thermal Sunyaev-Zeldovich (TSZ) effect at the 15$σ$ level, the highest statistical significance reported so far. Owing to the large size of our cluster sample, we are able to detect the corresponding CMB distortions out to large cluster-centric radii. The region over which the TSZ signal is detected is, on average, four times larger in radius than the X-ray emitting region, extending to $\sim 3h_{70}^{-1}$Mpc. We show that an isothermal $β$ model does not fit the electron pressure at large radii; instead, the baryon profile is consistent with the Navarro-Frenk-White profile, expected for dark matter in the concordance $Λ$CDM model. The X-ray temperature at the virial radius of the clusters falls by a factor $\sim 3-4$ from the central value, depending on the cluster concentration parameter. Our results suggest that cluster dynamics at large radii is dominated by dark matter and is well described by Newtonian gravity.

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