Cosmological constraints from the 100-deg2 weak-lensing survey
Cosmological constraints from the 100-deg2 weak-lensing survey
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DOI：
10.1111/j.1365-2966.2007.12202.x
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发表时间：
2007-03
影响因子：
4.8
通讯作者：
J. Benjamin;C. Heymans;E. Semboloni;L. Waerbeke;H. Hoekstra;T. Erben;M. Gladders;M. Hetterscheidt-M.-Hettersc
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文献类型：
--
作者：
J. Benjamin;C. Heymans;E. Semboloni;L. Waerbeke;H. Hoekstra;T. Erben;M. Gladders;M. Hetterscheidt-M.-Hettersc
我们提出了一个宇宙剪切分析的100度2弱透镜调查，结合CFHTLS宽，RCS，VIRMOS-DESCART和GaBoDS调查的数据。跨度为100 deg 2，源红移中值为10.78，这一组合测量使我们能够对物质密度参数Ω m和物质功率谱的振幅σ 8进行严格的联合约束，发现σ 8（Ω m /0.24）0.59 = 0.84 ±0.05。每个调查的实测剪切相关函数和计算协方差矩阵的表格作为本文在线版本的补充材料。我们的结果的准确性是一个显着的改善，由于在我们的分析三个重要的差异，以前的工作：我们正确地考虑样本方差误差，包括从数值模拟估计的非高斯贡献，我们校正了测量的剪切校准偏差估计从模拟数据;我们从CFHTLS-Deep目前可获得的最大的深测光红移目录中模拟了每次测量的红移分布n（z）。该星表是随机抽样的，以再现每次调查的震级分布，并使用两种不同的模型对所得到的调查相关的n（z）进行参数化。虽然我们的结果是一致的n（z）模型测试，我们发现，我们的宇宙学参数的约束弱依赖于（在5%的水平）的包含或排除星系的低置信度光度红移估计（z > 1.5）。这些高红移星系的数量相对较少，但贡献了显着的弱透镜信号。因此，对于未来的弱透镜巡天来说，获得近红外数据以在宇宙剪切分析中可靠地确定高红移星系的数量是很重要的。
We present a cosmic shear analysis of the 100-deg 2 weak-lensing survey, combining data from the CFHTLS-Wide, RCS, VIRMOS-DESCART and GaBoDS surveys. Spanning ∼100 deg 2 , with a median source redshift ∼0.78, this combined survey allows us to place tight joint constraints on the matter density parameter Ω m , and the amplitude of the matter power spectrum σ 8 , finding σ 8 (Ω m /0.24) 0.59 = 0.84 ±0.05. Tables of the measured shear correlation function and the calculated covariance matrix for each survey are included as supplementary material to the online version of this article. The accuracy of our results is a marked improvement on previous work owing to three important differences in our analysis; we correctly account for sample variance errors by including a non-Gaussian contribution estimated from numerical simulations; we correct the measured shear for a calibration bias as estimated from simulated data; we model the redshift distribution, n(z), of each survey from the largest deep photometric redshift catalogue currently available from the CFHTLS-Deep. This catalogue is randomly sampled to reproduce the magnitude distribution of each survey with the resulting survey-dependent n(z) parametrized using two different models. While our results are consistent for the n(z) models tested, we find that our cosmological parameter constraints depend weakly (at the 5 per cent level) on the inclusion or exclusion of galaxies with low-confidence photometric redshift estimates (z > 1.5). These high-redshift galaxies are relatively few in number but contribute a significant weak-lensing signal. It will therefore be important for future weak-lensing surveys to obtain near-infrared data to reliably determine the number of high-redshift galaxies in cosmic shear analyses.