HICOSMO – cosmology with a complete sample of galaxy clusters – I. Data analysis, sample selection and luminosity–mass scaling relation
HICOSMO – cosmology with a complete sample of galaxy clusters – I. Data analysis, sample selection and luminosity–mass scaling relation
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DOI：
10.1093/mnras/stx1022
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发表时间：
2017-05
影响因子：
4.8
通讯作者：
G. Schellenberger;T. Reiprich
中科院分区：
文献类型：
--
作者：
G. Schellenberger;T. Reiprich
在X射线系统中，星系团中质量最大的可见成分--星系团内介质(ICM)是可见的，它提供了直接测量的量，如光度，以及导出量，如总质量，以表征这些天体。这个项目的目的是详细分析一个完整的星系团样本，并限制宇宙学参数，如物质密度，欧米伽，或初始密度波动的幅度，sigma8。纯X射线通量受限样本(HIFLUGCS)由X射线最亮星系团组成，这些星系团是研究系统效应的极佳靶标，会对结果产生偏差。我们分析了总共196个HIFLUGCS星系团的钱德拉观测，总曝光时间为7.7ms。在这里，我们介绍了我们的数据分析程序(包括自动子结构检测和表面亮度剖面分析的能带优化)，给出了单独确定的、稳健的总质量估计。这些质量与动力学质量和Planck Sunyaev-Zeldovich(SZ)得出的相同星系团的质量进行了比较，发现它们与动力学质量总体上是一致的。普朗克SZ质量似乎显示出与流体静力质量有关的偏差；讨论了这种质量-质量比较中可能存在的偏差，包括普朗克选择函数。此外，我们还给出了0.1-2.4keV发光度与质量标度关系的结果。样本的总体斜率(1.34)与预期和文献中的值是一致的。将样本分成星系组和星系团显示，即使在选择偏差校正之后，星系组显示出比星系团(1.06)明显更陡峭的斜率(1.88)。
The X-ray regime, where the most massive visible component of galaxy clusters, the intra cluster medium (ICM), is visible, offers directly measured quantities, like the luminosity, and derived quantities, like the total mass, to characterize these objects. The aim of this project is to analyze a complete sample of galaxy clusters in detail and constrain cosmological parameters, like the matter density, OmegaM, or the amplitude of initial density fluctuations, sigma8. The purely X-ray flux-limited sample (HIFLUGCS) consists of the 64 X-ray brightest galaxy clusters, which are excellent targets to study the systematic effects, that can bias results. We analyzed in total 196 Chandra observations of the 64 HIFLUGCS clusters, with a total exposure time of 7.7 Ms. Here we present our data analysis procedure (including an automated substructure detection and an energy band optimization for surface brightness profile analysis) which gives individually determined, robust total mass estimates. These masses are tested against dynamical and Planck Sunyaev-Zeldovich (SZ) derived masses of the same clusters, where good overall agreement is found with the dynamical masses. The Planck SZ masses seem to show a mass dependent bias to our hydrostatic masses; possible biases in this mass-mass comparison are discussed including the Planck selection function. Furthermore, we show the results for the 0.1-2.4-keV-luminosity vs. mass scaling-relation. The overall slope of the sample (1.34) is in agreement with expectations and values from literature. Splitting the sample into galaxy groups and clusters reveals, even after a selection bias correction, that galaxy groups exhibit a significantly steeper slope (1.88) compared to clusters (1.06).