NOISY WEAK-LENSING CONVERGENCE PEAK STATISTICS NEAR CLUSTERS OF GALAXIES AND BEYOND
NOISY WEAK-LENSING CONVERGENCE PEAK STATISTICS NEAR CLUSTERS OF GALAXIES AND BEYOND
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星系团附近及其以外的嘈杂弱透镜收敛峰值统计数据
DOI：
10.1088/0004-637x/719/2/1408
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发表时间：
2010-06
影响因子：
4.9
通讯作者：
Shan, Huanyuan
中科院分区：
文献类型：
--
作者：
Liu, Jiayi;Fan, Zuhui;Shan, Huanyuan
考虑到来自源星系固有椭圆率的噪声，在本文中，我们研究了星系团周围及其以外的弱透镜汇聚图中的峰值统计数据。我们强调噪声峰值统计数据如何受到附近簇的密度分布的影响，以及簇峰值信号如何因噪声的存在而改变。这些是在单个星团的弱透镜分析以及弱透镜星团统计的宇宙学应用中需要彻底理解的重要方面。在我们的分析中，我们采用平滑尺度 θG = 0.5arcmin 的高斯平滑。研究发现，星系团附近的噪声峰值分布敏感地依赖于星系团的密度剖面。对于核心半径为 Rc 的核心等温星团，R ⩽ Rc 的内部区域出现噪声，平均包含 ∼2.4 个峰值，其中 ν ⩾ 5（Rc = 1.7arcmin），簇的真实峰值高度 ν = 5.6，其中 ν 表示收敛信噪比。对于具有相同质量和相同中心 ν 的纳瓦罗-弗伦克-怀特 (NFW) 簇，R ⩽ Rc 内 ν ⩾ 5 的峰的平均数量为 ∼1.6。因此，在 NFW 情况下可以更清楚地识别与主簇相对应的高峰值。在 Rc < R ≤ 5Rc 的外部区域中，与没有附近簇的纯噪声情况相比，高噪声峰值的数量显着增加。对于 ν ⩾ 4，根据弱透镜分析中质量片简并性的处理，两个星团的增强因子 f 在 ∼5 到 ∼55 的范围内，因为它们的外部密度分布相似。收敛图中识别的主簇峰的特性也受到噪声存在的显着影响。存在分散以及峰高的系统偏移。对于等温星团，高度分布在 ν ∼ 6.6 处达到峰值，而不是在 ν = 5.6 处，对应于 Δν ∼ 1 的偏移。对于 NFW 集群，Δν ∼ 0.8。噪声的存在还会导致弱透镜识别的主簇峰相对于簇的真实中心的位置偏移。对于等温情况，偏移分布非常广泛，延伸至 R ∼ Rc。对于 NFW 簇，它相对较窄，在 R ∼ 0.2Rc 处达到峰值。我们还分析了不同浓度的 NFW 簇。研究发现，星团的质量分布越集中，其弱透镜信号受噪声的影响越小。结合这些重要效应和 NFW 暗物质晕的质量函数，我们进一步提出了一个模型，计算在单个簇之外的大范围内总收敛峰（真峰和假峰）的统计丰度。结果与数值模拟的结果非常吻合。然后，该模型允许我们直接用收敛峰探测宇宙学，而不需要昂贵的后续观测来区分真峰和假峰。
Taking into account noise from intrinsic ellipticities of source galaxies, in this paper, we study the peak statistics in weak-lensing convergence maps around clusters of galaxies and beyond. We emphasize how the noise peak statistics is affected by the density distribution of nearby clusters, and also how cluster-peak signals are changed by the existence of noise. These are the important aspects to be thoroughly understood in weak-lensing analyses for individual clusters as well as in cosmological applications of weak-lensing cluster statistics. We adopt Gaussian smoothing with the smoothing scale θG = 0.5arcmin in our analyses. It is found that the noise peak distribution near a cluster of galaxies sensitively depends on the density profile of the cluster. For a cored isothermal cluster with the core radius Rc, the inner region with R ⩽ Rc appears noisy containing on average ∼2.4 peaks with ν ⩾ 5 for Rc = 1.7arcmin and the true peak height of the cluster ν = 5.6, where ν denotes the convergence signal-to-noise ratio. For a Navarro–Frenk–White (NFW) cluster of the same mass and the same central ν, the average number of peaks with ν ⩾ 5 within R ⩽ Rc is ∼1.6. Thus a high peak corresponding to the main cluster can be identified more cleanly in the NFW case. In the outer region with Rc < R ⩽ 5Rc, the number of high noise peaks is considerably enhanced in comparison with that of the pure noise case without the nearby cluster. For ν ⩾ 4, depending on the treatment of the mass-sheet degeneracy in weak-lensing analyses, the enhancement factor f is in the range of ∼5 to ∼55 for both clusters as their outer density profiles are similar. The properties of the main-cluster-peak identified in convergence maps are also significantly affected by the presence of noise. Scatters as well as a systematic shift for the peak height are present. The height distribution is peaked at ν ∼ 6.6, rather than at ν = 5.6, corresponding to a shift of Δν ∼ 1, for the isothermal cluster. For the NFW cluster, Δν ∼ 0.8. The existence of noise also causes a location offset for the weak-lensing identified main-cluster-peak with respect to the true center of the cluster. The offset distribution is very broad and extends to R ∼ Rc for the isothermal case. For the NFW cluster, it is relatively narrow and peaked at R ∼ 0.2Rc. We also analyze NFW clusters of different concentrations. It is found that the more centrally concentrated the mass distribution of a cluster is, the less its weak-lensing signal is affected by noise. Incorporating these important effects and the mass function of NFW dark matter halos, we further present a model calculating the statistical abundances of total convergence peaks, true and false ones, over a large field beyond individual clusters. The results are in good agreement with those from numerical simulations. The model then allows us to probe cosmologies with the convergence peaks directly without the need of expensive follow-up observations to differentiate true and false peaks.
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DOI：
10.1088/0004-637x/699/2/958
发表时间：
2008-12
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Lei Sun;Z. Fan;C. Tao;J. Kneib;S. Jouvel;A. Tilquin
通讯作者：
Lei Sun;Z. Fan;C. Tao;J. Kneib;S. Jouvel;A. Tilquin
DOI：
10.1111/j.1365-2966.2008.13880.x
发表时间：
2007-10
影响因子：
4.8
作者：
A. Amara;A. Réfrégier
通讯作者：
A. Amara;A. Réfrégier
DOI：
10.1088/0004-637x/698/1/l33
发表时间：
2008-11
期刊：
The Astrophysical Journal
影响因子：
--
作者：
L. Marian;R. Smith;G. Bernstein
通讯作者：
L. Marian;R. Smith;G. Bernstein
DOI：
10.1086/172297
发表时间：
1993-02
期刊：
The Astrophysical Journal
影响因子：
--
作者：
N. Kaiser;G. Squires
通讯作者：
N. Kaiser;G. Squires
影响因子：
6.5
作者：
L. Fu;L. Fu;E. Semboloni;E. Semboloni;H. Hoekstra;M. Kilbinger;M. Kilbinger;L. Waerbeke;I. Ter
通讯作者：
L. Fu;L. Fu;E. Semboloni;E. Semboloni;H. Hoekstra;M. Kilbinger;M. Kilbinger;L. Waerbeke;I. Ter