光学合并星系团的晕浓度、星系红分数和气体性质
Halo Concentration, Galaxy Red Fraction, and Gas Properties of Optically-defined Merging Clusters
摘要:
我们提出了多波长的光学定义的合并集群的研究,基于超至尊凸轮斯巴鲁战略计划。明亮的红色星系,跟踪集群质量分布,使识别集群subhalos在不同的合并阶段,从而使一个均匀的样本的集群合并,这是公正的合并促进集群内介质(ICM)。我们定义,使用一个峰值发现的方法,合并集群与多峰和单集群与单峰的CAMIRA集群目录。堆叠弱透镜分析表明,我们的合并集群的样本被归类为主要的合并。合并团簇的平均晕浓度比单峰团簇的平均晕浓度小$\sim70\%$,这与数值模拟的结果吻合较好。次晕的空间分布不如主晕的质量分布集中。合并星系团中红星系的比例并不高于单峰星系团。我们发现了一个签名的合并提升的ICM堆叠普朗克Sunyaev-Zeldovich效应和ROSAT X射线光度,但不是在光学丰富度。堆叠的X射线表面亮度分布,与低红移和大质量星系团的主-次晕对对齐,表明中心气体核心沿合并轴拉长,整体气体分布错位$\sim60$度。均匀,无偏的集群合并和多波长的后续研究的样本提供了一个独特的机会,使合并物理的整个过程的全貌。
英文摘要:
We present multi-wavelength studies of optically-defined merging clusters, based on the Hyper Suprime-Cam Subaru Strategic Program. Luminous red galaxies, tracing cluster mass distributions, enable to identify cluster subhalos at various merging stages, and thus make a homogeneous sample of cluster mergers, which is unbiased with respect to the merger boost of the intracluster medium (ICM). We define, using a peak-finding method, merging clusters with multiple-peaks and single clusters with single-peaks from the CAMIRA cluster catalog. Stacked weak-lensing analysis indicates that our sample of the merging clusters is categorized into major mergers. The average halo concentration for the merging clusters is $\sim70\%$ smaller than that of the single-peak clusters, which agrees well with predictions of numerical simulations. The spatial distribution of subhalos is less centrally concentrated than the mass distribution of the main halo. The fractions of red galaxies in the merging clusters are not higher than those of the single-peak clusters. We find a signature of the merger boost of the ICM from stacked Planck Sunyaev-Zeldovich effect and ROSAT X-ray luminosity, but not in optical richness. The stacked X-ray surface brightness distribution, aligned with the main-subhalo pairs of low redshift and massive clusters, shows that the central gas core is elongated along the merger axis and overall gas distribution is misaligned by $\sim60$ deg. The homogeneous, unbiased sample of cluster mergers and multi-wavelength follow-up studies provide a unique opportunity to make a complete picture of merger physics over the whole process.
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