The Surprisingly Steep Mass Profile of A1689, from a Lensing Analysis of Subaru Images
The Surprisingly Steep Mass Profile of A1689, from a Lensing Analysis of Subaru Images
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DOI：
10.1086/428122
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发表时间：
2004-12
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影响因子：
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通讯作者：
T. Broadhurst;Masahiro Takada;K. Umetsu;Xu Kong;N. Arimoto;Masashi Chiba;Toshifumi Futamase Tohoku Univ.;T. Univ.;Asiaa;Naoj
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文献类型：
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作者：
T. Broadhurst;Masahiro Takada;K. Umetsu;Xu Kong;N. Arimoto;Masashi Chiba;Toshifumi Futamase Tohoku Univ.;T. Univ.;Asiaa;Naoj
Subaru 对 A1689 (z = 0.183) 的观测结果用于通过结合放大偏差和畸变测量来导出整个星团的精确的、与模型无关的质量分布，r ≲ 2 Mpc h-1。随着半径的增加，预测的质量分布迅速变陡，在 r ~ 1.0 Mpc h-1 处降至零，远低于预期的维里半径。我们的轮廓与内部轮廓精确匹配，r ≲ 200 kpc h-1，源自哈勃太空望远镜高级巡天相机 (ACS) 图像。 ACS 和 Subaru 的综合信息与维里质量 (1.93 ± 0.20) × 1015 M☉ 的 Navarro-Frenk-White 剖面很好地吻合，浓度高得惊人，cvir = 13.7，显着大于理论预期 (cvir ≃ 4)，对应于相对陡峭的整体剖面。使用陡峭幂律模型 d log Σ(θ)/d log θ ≃ -3，核心 θc ≃ 1.′7 (rc ≃ 210 kpc h-1) 可以实现稍微更好的拟合，而等温剖面则被强烈拒绝。这些结果基于选择比星团 E/S0 序列更红的背景星系的可靠样本。通过包含微弱的蓝色星系群，发现了一个小得多的失真信号，表明蓝色星团成员显着稀释了 r ≲ 400 kpc h-1 的真实信号。这种污染可能会影响迄今为止最弱的透镜结果。
Subaru observations of A1689 (z = 0.183) are used to derive an accurate, model-independent mass profile for the entire cluster, r ≲ 2 Mpc h-1, by combining magnification bias and distortion measurements. The projected mass profile steepens quickly with increasing radius, falling away to zero at r ~ 1.0 Mpc h-1, well short of the anticipated virial radius. Our profile accurately matches the inner profile, r ≲ 200 kpc h-1, derived from deep Hubble Space Telescope Advanced Camera for Surveys (ACS) images. The combined ACS and Subaru information is well fitted by a Navarro-Frenk-White profile with virial mass, (1.93 ± 0.20) × 1015 M☉, and surprisingly high concentration, cvir = 13.7, significantly larger than theoretically expected (cvir ≃ 4), corresponding to a relatively steep overall profile. A slightly better fit is achieved with a steep power-law model, d log Σ(θ)/d log θ ≃ -3, with a core θc ≃ 1.′7 (rc ≃ 210 kpc h-1), whereas an isothermal profile is strongly rejected. These results are based on a reliable sample of background galaxies selected to be redder than the cluster E/S0 sequence. By including the faint blue galaxy population, a much smaller distortion signal is found, demonstrating that blue cluster members significantly dilute the true signal for r ≲ 400 kpc h-1. This contamination is likely to affect most weak lensing results to date.