Weak Gravitational Lensing and X-Ray Analysis of Abell 2163
Weak Gravitational Lensing and X-Ray Analysis of Abell 2163
复制标题
Abell 2163 的弱引力透镜和 X 射线分析
DOI：
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发表时间：
1996
期刊：
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通讯作者：
D. Woods
中科院分区：
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作者：
G. Squires;D. Neumann;N. Kaiser;N. Kaiser;M. Arnaud;Arif Babul;H. Böhringer;G. Fahlman;G. Fahlman;D. Woods
本文报道了利用背景星系的弱引力畸变和星系团X射线辐射分析探测星系团阿贝尔2163中的暗物质。我们发现，虽然集群光和暗物质的定性分布是相似的浅和扩展，具有显着的子结构的X射线形态显示出更有规律的整体外观。我们解释联合透镜和X射线观测的一个签名的合并事件的集群。我们提出了新的ROSAT/HRI数据和重新分析ROSAT/PSPC数据，考虑到不同背景的影响，以确定β模型形式主义中的最佳拟合参数。我们结合联合收割机的表面亮度适合两个测定的径向温度分布使用先进的宇宙学和天体物理卫星和Ginga数据，以确定总质量。尽管β拟合中的不确定性导致总质量测定值略有变化，但对误差的主要贡献来自温度测定中的不确定性。尽管暗物质/光和X射线气体的形态有些不同，我们发现从X射线和弱透镜估计确定的总质量在2 σ误差条内是一致的，X射线推断的质量大了102倍。然而，由于透镜质量估计是差分的（任何点处的表面密度相对于控制环中的平均值来确定），质量分布的浅的、延伸的性质使透镜推断的质量向下偏置。我们估计这种效果的校正，并发现校正透镜和X射线结果之间非常好的协议。我们测定了该星系团的气体质量分数，发现在所有半径上，fg = 0.07 h-3/2，质量光比为（300 ± 100）h M/L/V。
We report on the detection of dark matter in the cluster of galaxies Abell 2163 using the weak gravitational distortion of background galaxies and an analysis of the X-ray emission from the cluster. We find that while the qualitative distributions of the cluster light and the dark matter are similar—shallow and extended, with significant substructure—the X-ray morphology shows a more regular overall appearance. We interpret the joint lensing and X-ray observations as a signature of a merger event in the cluster. We present new ROSAT/HRI data and reanalyze ROSAT/PSPC data, accounting for the effect of a varying background to determine the best-fit parameters in the β-model formalism. We combine the surface brightness fits with two determinations of the radial temperature profile using Advanced Satellite for Cosmology and Astrophysics and Ginga data to determine the total mass. Although there are slight variations in the total mass determinations introduced by the uncertainties in the β-fit, the main contribution to the error arises from the uncertainties in the temperature determinations. Even though the morphologies of the dark matter/light and X-ray gas are somewhat different, we find that the total mass determined from the X-ray and weak lensing estimates are consistent with each other within the 2 σ error bars, with the X-ray inferred mass a factor of ≃2 larger. However, since the lensing mass estimates are differential (the surface density at any point is determined relative to the mean in a control annulus), the shallow, extended nature of the mass profile biases the lensing inferred mass downward. We estimate the correction for this effect and find very good agreement between the corrected lensing and X-ray results. We determine the gas mass fraction in this cluster and find fg ≃ 0.07 h-3/2 at all radii and a constant mass-to-light ratio of M/LV = (300 ± 100) h M/L☉V.