Dark Energy Survey year 1 results: Cosmological constraints from galaxy clustering and weak lensing
Dark Energy Survey year 1 results: Cosmological constraints from galaxy clustering and weak lensing
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DOI：
10.1103/physrevd.98.043526
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发表时间：
2017-08
影响因子：
5
通讯作者：
T. Abbott;F. Abdalla;A. Alarcon;J. Aleksić;S. Allam;S. Allen;A. Amara;J. Annis;J. Asorey-J.-As
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文献类型：
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作者：
T. Abbott;F. Abdalla;A. Alarcon;J. Aleksić;S. Allam;S. Allen;A. Amara;J. Annis;J. Asorey-J.-As
我们目前的宇宙学结果的星系聚类和弱引力透镜的综合分析，使用1321 deg 2的格里兹成像数据的第一年的暗能量调查（DES Y1）。我们结合联合收割机三个两点函数：（i）宇宙剪切相关函数的2600万个源星系在四个红移箱，（ii）星系角自相关函数的650,000个明亮的红色星系在五个红移箱，和（iii）星系剪切交叉相关的明亮的红色星系的位置和源星系剪切。为了证明这些结果的鲁棒性，我们使用独立的对星系的形状，光度红移估计和验证，和似然分析管道。为了防止确认偏倚，大部分分析是在对真实结果“盲态”的情况下进行的;我们描述了在盲态阶段进行并通过的一系列系统学检查。数据在平坦的ΛCDM和wCDM宇宙学中建模，边缘化了20多个讨厌的参数，改变了6个（对于ΛCDM）或7个（对于wCDM）宇宙学参数，包括中微子质量密度和457×457元素解析协方差矩阵。我们从这三个两点函数中找到了一致的宇宙学结果，并从它们的组合中得到了S8 <$σ8（Ωm/0.3）0.5=0.773-0.020+0.026和Ωm=0.267-0.017+0.030;在68% C. L时，wCDM的S_8 =0.782-0.024+0.036，Ωm=0.284-0.030+0.033，w=-0.82-0.20+0.21。这些DES Y1约束的精度与普朗克宇宙微波背景测量的精度不相上下，允许在同等条件下比较非常早期和晚期宇宙的结构。虽然DES Y1对S8和Ωm的最佳拟合值低于普朗克对ΛCDM和wCDM的中心值，但贝叶斯因子表明DES Y1和普朗克数据集在ΛCDM的背景下彼此一致。结合DES Y1和普朗克，SDSS，6dF和BOSS的重子声振荡测量以及联合光曲分析数据集的Ia型超新星，我们得到了非常严格的宇宙学参数约束：在ΛCDM中S_8 =0.802±0.012，Ωm=0.298±0.007，在wCDM中w=-1.00-0.04+0.05。即将到来的暗能量调查分析将提供对ΛCDM模型和扩展的更严格的测试，例如暗能量或修正引力的时变状态方程。
We present cosmological results from a combined analysis of galaxy clustering and weak gravitational lensing, using 1321 deg2 of griz imaging data from the first year of the Dark Energy Survey (DES Y1). We combine three two-point functions: (i) the cosmic shear correlation function of 26 million source galaxies in four redshift bins, (ii) the galaxy angular autocorrelation function of 650,000 luminous red galaxies in five redshift bins, and (iii) the galaxy-shear cross-correlation of luminous red galaxy positions and source galaxy shears. To demonstrate the robustness of these results, we use independent pairs of galaxy shape, photometric-redshift estimation and validation, and likelihood analysis pipelines. To prevent confirmation bias, the bulk of the analysis was carried out while “blind” to the true results; we describe an extensive suite of systematics checks performed and passed during this blinded phase. The data are modeled in flat ΛCDM and wCDM cosmologies, marginalizing over 20 nuisance parameters, varying 6 (for ΛCDM) or 7 (for wCDM) cosmological parameters including the neutrino mass density and including the 457×457 element analytic covariance matrix. We find consistent cosmological results from these three two-point functions and from their combination obtain S8≡σ8(Ωm/0.3)0.5=0.773-0.020+0.026 and Ωm=0.267-0.017+0.030 for ΛCDM; for wCDM, we find S8=0.782-0.024+0.036, Ωm=0.284-0.030+0.033, and w=-0.82-0.20+0.21 at 68% C.L. The precision of these DES Y1 constraints rivals that from the Planck cosmic microwave background measurements, allowing a comparison of structure in the very early and late Universe on equal terms. Although the DES Y1 best-fit values for S8 and Ωm are lower than the central values from Planck for both ΛCDM and wCDM, the Bayes factor indicates that the DES Y1 and Planck data sets are consistent with each other in the context of ΛCDM. Combining DES Y1 with Planck, baryonic acoustic oscillation measurements from SDSS, 6dF, and BOSS and type Ia supernovae from the Joint Lightcurve Analysis data set, we derive very tight constraints on cosmological parameters: S8=0.802±0.012 and Ωm=0.298±0.007 in ΛCDM and w=-1.00-0.04+0.05 in wCDM. Upcoming Dark Energy Survey analyses will provide more stringent tests of the ΛCDM model and extensions such as a time-varying equation of state of dark energy or modified gravity.