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arXiv 1001.2402astro-ph.CO
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用Subaru/Suprime-Cam测量COMA团簇中子结构的弱透镜质量

Weak Lensing Mass Measurements of Substructures in COMA Cluster with Subaru/Suprime-Cam

Nobuhiro Okabe, Yuki Okura, Toshifumi Futamase

摘要:

通过弱透镜分析,我们得到了后发座星系团(z=0.0236)西南区域(r \simlt 60 ')的两个Subaru/Suprime-Cam场的投影质量分布,并探测到8个候选子星系团。在场星系质光比的假设下,利用SDSS多波段和光度数据定量分析了背景大尺度结构(LSS)对投影质量分布的贡献。我们发现,八个子团候选人,这是不相关的任何成员星系,是显着的LSS透镜的影响。从主星系团势中提取的7个亚团的平均投影质量为<M_2D^(corr)> =(5.06 \pm 1.30)10^12 h ^-1 M_sun。切向畸变分布在一个合奏的子块是很好的描述截断奇异等温球模型和截断NFW模型。在不假定成员星系的质量和光之间存在任何关系的情况下,我们推导出了典型的子团截断半径r_t \simeq 35 h^-1 kpc。该半径与主星团引力的潮汐半径\sim 42 h^-1 kpc非常吻合。考虑到数据区域的不完整性,投影效应和虚假的透镜峰,预计集团子结构的质量占维里质量的19%,统计误差为13%。团簇子结构的质量分数与数值模拟结果基本一致。

英文摘要:

We obtain the projected mass distributions for two Subaru/Suprime-Cam fields in the southwest region (r\simlt 60') of the Coma cluster (z=0.0236) by weak lensing analysis and detect eight subclump candidates. We quantify the contribution of background large-scale structure (LSS) on the projected mass distributions using SDSS multi-bands and photometric data, under the assumption of mass-to-light ratio for field galaxies. We find that one of eight subclump candidates, which is not associated with any member galaxies, is significantly affected by LSS lensing. The mean projected mass for seven subclumps extracted from the main cluster potential is <M_2D^(corr)> = (5.06\pm1.30)10^12h^-1 M_sun after a LSS correction. A tangential distortion profile over an ensemble of subclumps is well described by a truncated singular-isothermal sphere model and a truncated NFW model. A typical truncated radius of subclumps, r_t\simeq 35 h^-1 kpc, is derived without assuming any relations between mass and light for member galaxies. The radius coincides well with the tidal radius, \sim42 h^-1 kpc, of the gravitational force of the main cluster. Taking into account the incompleteness of data area, a projection effect and spurious lensing peaks, it is expected that mass of cluster substructures account for 19 percent of the virial mass, with 13 percent statistical error. The mass fraction of cluster substructures is in rough agreement with numerical simulations.

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