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arXiv 1102.1837astro-ph.CO
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Abell 383星系团的弱透镜分析

A weak lensing analysis of the Abell 383 cluster

Zhuoyi Huang, Mario Radovich, Aniello Grado, Emanuella Puddu, Anna Romano, Luca Limatola, Liping Fu

摘要:

在本文中,我们使用深CFHT和SUBARU $uBVRIz$档案图像的阿贝尔383集群(z=0.187),估计其质量的弱透镜。为此,我们首先使用模拟图像来检查KSB管道提供的准确性。这些模拟包括STEP 1和STEP 2模拟,以及对具有Navarro-Frenk-White(NFW)轮廓的星系团扭曲星系形状的更真实的模拟。从这样的模拟,我们估计剪切测量的噪声的影响,并推导出校正项。R波段图像用于通过将观察到的切向剪切剖面与NFW质量剖面拟合来推导质量。测光红移是从uBVRIz星表计算的。实现了前景/背景星系选择的不同方法,即通过星等、颜色和光度红移进行选择,并对结果进行了比较。特别是,我们开发了一种半自动算法来选择前景星系的颜色-颜色图,根据观察到的颜色。使用颜色选择或光度红移改善了对前景星系稀释的校正:这导致了星系团内部更高的信号。我们得到的星团质量比以前的估计高出约20%,并且与X射线数据的预期质量更一致。最后计算了该星系团的R带光度函数。

英文摘要:

In this paper we use deep CFHT and SUBARU $uBVRIz$ archival images of the Abell 383 cluster (z=0.187) to estimate its mass by weak lensing. To this end, we first use simulated images to check the accuracy provided by our KSB pipeline. Such simulations include both the STEP 1 and 2 simulations, and more realistic simulations of the distortion of galaxy shapes by a cluster with a Navarro-Frenk-White (NFW) profile. From such simulations we estimate the effect of noise on shear measurement and derive the correction terms. The R-band image is used to derive the mass by fitting the observed tangential shear profile with a NFW mass profile. Photometric redshifts are computed from the uBVRIz catalogs. Different methods for the foreground/background galaxy selection are implemented, namely selection by magnitude, color and photometric redshifts, and results are compared. In particular, we developed a semi-automatic algorithm to select the foreground galaxies in the color-color diagram, based on observed colors. Using color selection or photometric redshifts improves the correction of dilution from foreground galaxies: this leads to higher signals in the inner parts of the cluster. We obtain a cluster mass that is ~ 20% higher than previous estimates, and is more consistent the mass expected from X--ray data. The R-band luminosity function of the cluster is finally computed.

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