MORPHOLOGY OF GALAXY CLUSTERS: A COSMOLOGICAL MODEL-INDEPENDENT TEST OF THE COSMIC DISTANCE–DUALITY RELATION
MORPHOLOGY OF GALAXY CLUSTERS: A COSMOLOGICAL MODEL-INDEPENDENT TEST OF THE COSMIC DISTANCE–DUALITY RELATION
复制标题
DOI：
10.1088/0004-637x/745/1/98
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Xiao-Lei Meng;Tong-Jie Zhang;H. Zhan;Xin Wang
中科院分区：
文献类型：
--
作者：
Xiao-Lei Meng;Tong-Jie Zhang;H. Zhan;Xin Wang
为了比较不同的星系团形态模型，我们采用两种新的方法对星系团的距离-对偶关系进行了与宇宙学模型无关的检验。光度距离来自Ia型超新星的Union2汇编。角直径距离由两个簇模型给出（De Filippis et al.和Bonamente et al.）。我们的方法的优点是可以减少统计误差。在聚类模型的形态学假设方面，主要对椭圆型β-模型和球形β-模型进行了比较。根据角直径距离减小方法的不同，将球面β-模型分为保守型球面β-模型和修正型球面β-模型两类。结果表明，两种方法在1σ置信水平（CL）下的DD关系与椭圆β-模型一致，而对于几乎所有的球面β-模型参数化，DD关系只能在3σ置信水平（CL）下被容纳，特别是对于保守的球面β-模型。为了最小化系统的不确定性，我们还将测试应用于重叠样本，即由De Filippis等人和Bonamente等人建模的同一组聚类。发现在1σ CL时，DD关系与椭圆模型的重叠样品相容；然而，对于大多数参数化，即使在3σ CL下，对于任何两个球面β-模型，DD关系也不能被容纳。因此，如果DD关系在宇宙学观测中是有效的，那么与球形β-模型相比，标记三轴椭球模型是一个更好的描述星系团结构的几何假设。
Aiming at comparing different morphological models of galaxy clusters, we use two new methods to make a cosmological model-independent test of the distance–duality (DD) relation. The luminosity distances come from the Union2 compilation of Supernovae Type Ia. The angular diameter distances are given by two cluster models (De Filippis et al. and Bonamente et al.). The advantage of our methods is that they can reduce statistical errors. Concerning the morphological hypotheses for cluster models, it is mainly focused on the comparison between the elliptical β-model and spherical β-model. The spherical β-model is divided into two groups in terms of different reduction methods of angular diameter distances, i.e., the conservative spherical β-model and corrected spherical β-model. Our results show that the DD relation is consistent with the elliptical β-model at 1σ confidence level (CL) for both methods, whereas for almost all spherical β-model parameterizations, the DD relation can only be accommodated at 3σ CL, particularly for the conservative spherical β-model. In order to minimize systematic uncertainties, we also apply the test to the overlap sample, i.e., the same set of clusters modeled by both De Filippis et al. and Bonamente et al. It is found that the DD relation is compatible with the elliptically modeled overlap sample at 1σ CL; however, for most of the parameterizations the DD relation cannot be accommodated even at 3σ CL for any of the two spherical β-models. Therefore, it is reasonable that the marked triaxial ellipsoidal model is a better geometrical hypothesis describing the structure of the galaxy cluster compared with the spherical β-model if the DD relation is valid in cosmological observations.