The 400d Galaxy Cluster Survey weak lensing programme - III. Evidence for consistent WL and X-ray masses at z ≈ 0.5
The 400d Galaxy Cluster Survey weak lensing programme - III. Evidence for consistent WL and X-ray masses at z ≈ 0.5
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DOI：
10.1051/0004-6361/201322870
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发表时间：
2014-02
影响因子：
6.5
通讯作者：
H. Israel;T. Reiprich;T. Erben;R. Massey;C. Sarazin;P. Schneider;A. Vikhlinin
中科院分区：
文献类型：
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作者：
H. Israel;T. Reiprich;T. Erben;R. Massey;C. Sarazin;P. Schneider;A. Vikhlinin
上下文星系团观测量与星系团质量的标度性质提供了核心的见解塑造集群的过程。此外，校准相对便宜的星团质量代理将是至关重要的，以收获宇宙学信息的数量和增长的集群与即将到来的调查，如eROSITA和欧几里得。最近的普朗克研究结果表明，X射线质量可能会有40%的偏差，比以前认为的要大。目标。我们的目标是在代表z 0：4 - 0：5人群的样本中，将弱透镜-X射线质量缩放的知识扩展到较低的质量（低至1 10 14 M）。因此，我们扩展了直接校准的集群质量估计更高的红移。方法.我们调查的MMT/Megacam弱透镜（WL）质量的标度行为为8个集群在0：39 z 0：80的400 d WL程序的一部分，流体静力学钱德拉X射线质量，以及那些基于代理，如YX = TXMgas。结果总体而言，我们发现WL和X射线质量之间的良好协议，与不同的质量偏差估计值都与零一致。当将样品细分为低质量和高质量子样品时，我们发现高质量子样品没有显示出显著的质量偏差，而对于低质量子样品，对于一些质量代理，在2级存在对高估X射线质量的偏差。质量-质量比例关系的总体离散度令人惊讶地低。调查可能的原因，我们发现，无论是更大的范围在WL比在X射线质量，也不是小的散射可以追溯到参数设置在WL分析。结论.我们没有发现证据的强烈（40%）低估的X射线质量，建议调和最近的普朗克集团计数和宇宙学约束。对于高质量的集群，我们的测量与文献中的其他研究一致。质量依赖性偏差（在2处显著）可能暗示了物理上不同的集群人口（具有更多子结构和合并的较不松弛的集群）;或者它可能是由于小的数字统计。对低质量高z透镜星系团的进一步研究将阐明它们的质量标度行为。
Context. Scaling properties of galaxy cluster observables with cluster mass provide central insights into the processes shaping clusters. Calibrating proxies for cluster mass that are relatively cheap to observe will moreover be crucial to harvest the cosmological information available from the number and growth of clusters with upcoming surveys like eROSITA and Euclid. The recent Planck results led to suggestions that X-ray masses might be biased low by 40%, more than previously considered. Aims. We aim to extend knowledge of the weak lensing ‐ X-ray mass scaling towards lower masses (as low as 1 10 14 M ) in a sample representative of the z 0:4‐0:5 population. Thus, we extend the direct calibration of cluster mass estimates to higher redshifts. Methods. We investigate the scaling behaviour of MMT/Megacam weak lensing (WL) masses for 8 clusters at 0:39 z 0:80 as part of the 400d WL programme with hydrostatic Chandra X-ray masses as well as those based on the proxies, e.g. YX = TXMgas. Results. Overall, we find good agreement between WL and X-ray masses, with di erent mass bias estimators all consistent with zero. When subdividing the sample into a low-mass and a high-mass subsample, we find the high-mass subsample to show no significant mass bias while for the low-mass subsample, there is a bias towards overestimated X-ray masses at the 2 level for some mass proxies. The overall scatter in the mass-mass scaling relations is surprisingly low. Investigating possible causes, we find that neither the greater range in WL than in X-ray masses nor the small scatter can be traced back to the parameter settings in the WL analysis. Conclusions. We do not find evidence for a strong ( 40%) underestimate in the X-ray masses, as suggested to reconcile recent Planck cluster counts and cosmological constraints. For high-mass clusters, our measurements are consistent with other studies in the literature. The mass dependent bias, significant at 2 , may hint at a physically di erent cluster population (less relaxed clusters with more substructure and mergers); or it may be due to small number statistics. Further studies of low-mass high-z lensing clusters will elucidate their mass scaling behaviour.