Dealing with systematics in cosmic shear studies: New results from the VIRMOS-Descart survey
Dealing with systematics in cosmic shear studies: New results from the VIRMOS-Descart survey
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DOI：
10.1051/0004-6361:20041513
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发表时间：
2004-06
影响因子：
6.5
通讯作者：
L. Waerbeke;Y. Mellier;H. Hoekstra
中科院分区：
文献类型：
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作者：
L. Waerbeke;Y. Mellier;H. Hoekstra
我们提出了一个重新分析的VIRMOS-Descart弱透镜数据，特别关注不同的校正的变化的点扩散函数各向异性（PSF）的CCD。我们表明，小尺度系统学可以最小化，并最终抑制，使用B模式（卷曲剪切分量）在校正的恒星和星系测量。更新的宇宙学约束，自由PSF各向异性引起的系统。为了便于我们的结果的一般使用，我们提供了两点统计数据点与他们的协方差矩阵的规模为一度。对于质量功率谱的归一化，我们得到σ8 =（0.83 ± 0.07）（μ M/0.3）−0.49。形状参数Γ在Γ ∈（0.1，0.3）上边缘化，平均源红移zs在（0.8，1.0）上边缘化。后者是一致的，最近的光度红移获得的VIRMOS数据和初步的光谱红移从VIRMOS-VVDS调查。引用的68%等值线水平包括所有已识别的误差源。我们讨论了可能的残留污染的来源，在这个结果：非线性质量功率谱的影响和剩余的问题有关的PSF校正。我们的结果进行了比较的威尔金森微波各向异性探针的第一个版本的数据。发现在3-σ处排除了具有幂律原始功率谱和高物质密度的冷暗物质模型。
We present a reanalysis of the VIRMOS-Descart weak lensing data, with a particular focus on different corrections for the variation of the point spread function anisotropy (PSF) across the CCDs. We show that the small scale systematics can be minimised, and eventually suppressed, using the B mode (curled shear component) measured in the corrected stars and galaxies. Updated cosmological constraints are obtained, free of systematics caused by PSF anisotropy. To facilitate general use of our results, we provide the two-points statistics data points with their covariance matrices up to a scale of one degree. For the normalisation of the mass power spectrum we obtain σ8 = (0.83 ± 0.07) (ΩM/0.3) −0.49 . The shape parameter Γ was marginalised over Γ ∈ (0.1, 0.3) and the mean source redshift zs over (0.8, 1.0). The latter is consistent with recent photometric redshifts obtained for the VIRMOS data and the preliminary spectroscopic redshifts from the VIRMOS-VVDS survey. The quoted 68% contour level includes all identified sources of error. We discuss the possible sources of residual contamination in this result: the effect of the non-linear mass power spectrum and remaining issues concerning the PSF correction. Our result is compared with the first release of the Wilkinson Microwave Anisotropy Probe data. It is found that Cold Dark Matter models with a power law primordial power spectrum and high matter density ΩM > 0.5 are excluded at 3-σ.