CFHTLenS: combined probe cosmological model comparison using 2D weak gravitational lensing
CFHTLenS: combined probe cosmological model comparison using 2D weak gravitational lensing
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DOI：
10.1093/mnras/stt041
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发表时间：
2012-12
影响因子：
4.8
通讯作者：
M. Kilbinger;L. Fu;C. Heymans;F. Simpson;J. Benjamin;T. Erben;J. Harnois-Déraps;H. Hoekstra
中科院分区：
文献类型：
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作者：
M. Kilbinger;L. Fu;C. Heymans;F. Simpson;J. Benjamin;T. Erben;J. Harnois-Déraps;H. Hoekstra
本文利用加拿大-法国-夏威夷望远镜透镜巡天（CFHTLenS）中的大尺度结构，给出了二维弱引力透镜的宇宙学约束。使用精确的光度红移和测量的420万个星系的红移为0.2和1.3之间的形状，我们计算的2D宇宙剪切相关函数的角尺度范围在0.8和350弧分之间。使用非线性模型的暗物质功率谱，我们约束宇宙学参数，探索参数空间与人口蒙特卡罗抽样。对于小尺度密度涨落振幅σ_8与总物质密度Ωm的比例关系，得到了单独透镜效应的最佳约束。对于平坦的Λ冷暗物质（ΛCDM）模型，我们得到σ 8（Ω m/0.27）0.6 = 0.79 ± 0.03。我们将CFHTLenS数据与7年威尔金森微波各向异性探测器（WMAP 7），重子声学振荡（BAO）：SDSS-III（BOSS）和哈勃空间望远镜距离阶梯结合在一起，以获得联合约束。对于平坦的ΛCDM模型，我们得到Ω m = 0.283 ± 0.010，σ 8 = 0.813 ± 0.014。在弯曲wCDM宇宙的情况下，我们得到Ω_m = 0.27 ± 0.03，σ_8 = 0.83 ± 0.04，w 0 = −1.10 ± 0.15和Ω_K = 0.006^（+0.006）_（− 0.004）.我们计算贝叶斯证据比较平坦和弯曲的ΛCDM和暗能量CDM模型。从所有四个探针的组合，我们发现模型的曲率是在适度不利的情况下，相对于平面。一个简单的暗能量模型与ΛCDM没有区别。因此，我们的结果不需要偏离标准宇宙学模型。
We present cosmological constraints from 2D weak gravitational lensing by the large-scale structure in the Canada–France–Hawaii Telescope Lensing Survey (CFHTLenS) which spans 154 deg^2 in five optical bands. Using accurate photometric redshifts and measured shapes for 4.2 million galaxies between redshifts of 0.2 and 1.3, we compute the 2D cosmic shear correlation function over angular scales ranging between 0.8 and 350 arcmin. Using non-linear models of the dark-matter power spectrum, we constrain cosmological parameters by exploring the parameter space with Population Monte Carlo sampling. The best constraints from lensing alone are obtained for the small-scale density-fluctuations amplitude σ_8 scaled with the total matter density Ωm. For a flat Λcold dark matter (ΛCDM) model we obtain σ_8(Ω_m/0.27)0.6 = 0.79 ± 0.03. We combine the CFHTLenS data with 7-year Wilkinson Microwave Anisotropy Probe (WMAP7), baryonic acoustic oscillations (BAO): SDSS-III (BOSS) and a Hubble Space Telescope distance-ladder prior on the Hubble constant to get joint constraints. For a flat ΛCDM model, we find Ω_m = 0.283 ± 0.010 and σ_8 = 0.813 ± 0.014. In the case of a curved wCDM universe, we obtain Ω_m = 0.27 ± 0.03, σ_8 = 0.83 ± 0.04, w0 = −1.10 ± 0.15 and Ω_K = 0.006^(+0.006)_(− 0.004). We calculate the Bayesian evidence to compare flat and curved ΛCDM and dark-energy CDM models. From the combination of all four probes, we find models with curvature to be at moderately disfavoured with respect to the flat case. A simple dark-energy model is indistinguishable from ΛCDM. Our results therefore do not necessitate any deviations from the standard cosmological model.