Weak-lensing study in VOICE survey - I. Shear measurement
Weak-lensing study in VOICE survey - I. Shear measurement
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VOICE 调查中的弱透镜研究 - I. 剪切测量
DOI：
10.1093/mnras/sty1579
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发表时间：
2018
影响因子：
4.8
通讯作者：
Giuliano
中科院分区：
文献类型：
--
作者：
Liping Fu;Dezi Liu;Mario Radovich;Xiangkun Liu;Chuzhong Pan;Zuhui Fan;Giovanni Covone;Mattia Vaccari;Valeria Amaro;Massimo Brescia;Massimo Capaccioli;Demetra De Cicco;Aniello Grado;Luca Limatola;Lance Miller;Nicola R. Napolitano;Maurizio Paolillo;Giuliano
CDFS和ES 1场的VST光学成像（VOICE）调查是一项保证时间计划，由欧洲南方天文台（ESO）VLT巡天望远镜（VST）望远镜进行，以提供以Chandra Deep Field South（CDFS）和ES 1为中心的两个4 deg 2天空区域的深层光学成像，作为ESO-Spitzer成像河外巡天的一部分。我们提出了宇宙剪切测量超过4 deg 2覆盖的CDFS区域在r波段使用LensFit。四个1度2的瓦片中的每一个都有超过100次曝光，其中超过50次曝光通过了弱透镜研究的一系列图像质量选择标准。点源在r波段的5σ极限星等为26.1等，比文献中的其他弱透镜巡天（如VST的Kilo Degree巡天（KiDS））深101等。光度红移是使用VOICE u、g、r、i和近红外视频数据Y、J、H、Ks估算的。考虑到剪切质量，剪切星表的平均红移为0.87。有效星系数密度为16.35 gal arcmin-2，几乎是KiDS的两倍。LensFit在这样一个深度数据集上的性能是使用类似VOICE的模拟图像模拟来校准的。此外，我们还通过计算恒星-星系的互相关、两个红移仓的层析剪切相关和混合星系的污染，分析了剪切星表的可靠性。作为进一步的健全性检查，我们已经约束宇宙学参数，通过探索参数空间与人口蒙特卡罗抽样。对于平坦的Λ冷暗物质模型，我们得到了Σ_8=σ_8（Ω_m/0.3）^{0.5}=0.68^{+0.11}_{-0.15}。
The VST Optical Imaging of the CDFS and ES1 Fields (VOICE) Survey is a Guaranteed Time programme carried out with the European Southern Observatory (ESO) VLT Survey Telescope (VST) telescope to provide deep optical imaging over two 4 deg2 patches of the sky centred on the Chandra Deep Field South (CDFS) and ES1 as part of the ESO-Spitzer Imaging Extragalactic Survey. We present the cosmic shear measurement over the 4 deg2 covering the CDFS region in the rband using LensFit. Each of the four tiles of 1 deg2 has more than 100 exposures, of which more than 50 exposures passed a series of image quality selection criteria for weak-lensing study. The 5σ limiting magnitude in r band is 26.1 for point sources, which is ≳1 mag deeper than other weak-lensing survey in the literature [e.g. the Kilo Degree Survey (KiDS) at VST]. The photometric redshifts are estimated using the VOICE u, g, r, i together with near-infrared VIDEO data Y, J, H, Ks. The mean redshift of the shear catalogue is 0.87, considering the shear weight. The effective galaxy number density is 16.35 gal arcmin-2, which is nearly twice the one of KiDS. The performance of LensFit on such a deep data set was calibrated using VOICE-like mock image simulations. Furthermore, we have analysed the reliability of the shear catalogue by calculating the star-galaxy cross-correlations, the tomographic shear correlations of two redshift bins and the contaminations of the blended galaxies. As a further sanity check, we have constrained cosmological parameters by exploring the parameter space with Population Monte Carlo sampling. For a flat Λ cold dark matter model, we have obtained Σ_8=σ_8(Ω_m/0.3)^{0.5}=0.68^{+0.11}_{-0.15}.