Lensing and x-ray mass estimates of clusters (simulations)
Lensing and x-ray mass estimates of clusters (simulations)
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DOI：
10.1088/1367-2630/14/5/055018
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发表时间：
2012-01
影响因子：
3.3
通讯作者：
E. Rasia;M. Meneghetti;R. Martino;S. Borgani;S. Borgani;A. Bonafede;K. Dolag;S. Ettori;D. Fabjan-D.
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文献类型：
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作者：
E. Rasia;M. Meneghetti;R. Martino;S. Borgani;S. Borgani;A. Bonafede;K. Dolag;S. Ettori;D. Fabjan-D.
我们给出了一个数值模拟星系团样本的弱透镜质量估计和X射线质量估计的比较。该样本由红移z=0.25Mvir>；5×1014M⊙h−1的20个最大质量天体组成。它们是在WMAP-7归一化宇宙学框架下演化的1h−3GPC3的宇宙学模拟中发现的。每个星系团都以更高的分辨率和更复杂的气体物理进行了重新模拟。我们通过Skylens和X-MAS对其进行处理，生成沿三个正交投影的光学和X射线模拟观测。最终样本由60个集群实现组成。光学模拟包括背景源上的透镜效应。使用标准观测工具和分析方法从模拟星表中恢复每个星团投影的质量轮廓。从透镜和x射线得到的质量分布分别与输入质量分布进行比较。考虑到我们的样本大小，我们还可以研究结果对团簇形态、环境、温度不均匀性和质量的依赖性。我们证实了先前的结果，即用纳瓦罗-弗伦克-怀特泛函拟合团簇切向剪切剖面得到的透镜质量偏低∼5-10%，而散射大(∼10-25%)。我们发现，通过优化选择具有规则形态或生活在子结构贫乏环境中的团簇，可以减少散射。X射线质量有很大的偏低(∼25-35%)，这证明了星团内介质中存在非热压源和温度不均匀，但它们的散射性明显低于弱透镜来源的质量。X射线质量偏差从团簇的内部区域向外部区域逐渐增大。我们发现，这两种偏差都与三阶功率比有较弱的相关性，而与质心位移有较强的相关性。最后，X射线偏置与温度不均匀性有很强的联系。与以前的模拟分析相比，模拟得到的x射线质量偏差值仍然是不确定的，这表明它依赖于ICM物理处理，也可能依赖于所采用的流体力学方案。
We present a comparison between weak-lensing and x-ray mass estimates of a sample of numerically simulated clusters. The sample consists of the 20 most massive objects at redshift z = 0.25 and Mvir > 5 × 1014M⊙ h−1. They were found in a cosmological simulation of volume 1 h−3 Gpc3, evolved in the framework of a WMAP-7 normalized cosmology. Each cluster has been resimulated at higher resolution and with more complex gas physics. We processed it through Skylens and X-MAS to generate optical and x-ray mock observations along three orthogonal projections. The final sample consists of 60 cluster realizations. The optical simulations include lensing effects on background sources. Standard observational tools and methods of analysis are used to recover the mass profiles of each cluster projection from the mock catalogue. The resulting mass profiles from lensing and x-ray are individually compared to the input mass distributions. Given the size of our sample, we could also investigate the dependence of the results on cluster morphology, environment, temperature inhomogeneity and mass. We confirm previous results showing that lensing masses obtained from the fit of the cluster tangential shear profiles with Navarro–Frenk–White functionals are biased low by ∼5–10% with a large scatter (∼10–25%). We show that scatter could be reduced by optimally selecting clusters either having regular morphology or living in substructure-poor environment. The x-ray masses are biased low by a large amount (∼25–35%), evidencing the presence of both non-thermal sources of pressure in the intra-cluster medium (ICM) and temperature inhomogeneity, but they show a significantly lower scatter than weak-lensing-derived masses. The x-ray mass bias grows from the inner to the outer regions of the clusters. We find that both biases are weakly correlated with the third-order power ratio, while a stronger correlation exists with the centroid shift. Finally, the x-ray bias is strongly connected with temperature inhomogeneities. Comparison with a previous analysis of simulations leads to the conclusion that the values of x-ray mass bias from simulations are still uncertain, showing dependences on the ICM physical treatment and, possibly, on the hydrodynamical scheme adopted.