Probing dark energy with the shear-ratio geometric test
Probing dark energy with the shear-ratio geometric test
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通过剪切比几何测试探测暗能量
DOI：
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发表时间：
2006
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通讯作者：
A. Heavens
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作者：
A. Taylor;T. Kitching;D. Bacon;A. Heavens
我们采用 Jain-Taylor (2003) 剪切比几何透镜方法来测量暗能量状态方程 w = pv /ρv 及其来自具有任意空间曲率的宇宙学中暗物质晕的时间导数。计算透镜源的完整剪切比协方差矩阵，包括作为附加噪声源的介入的大规模结构和光度红移误差，并提出了应用测试的最大似然方法。将透镜物质分布分解为暗物质晕，我们计算任意实验的参数协方差矩阵。结合宇宙微波背景（CMB）的预期结果，我们设计了探测暗能量的最佳调查。这表明，通过五波段光学光度红移对半球中 60 个最大星团进行有针对性的调查成像，中位星系深度为 Z m = 0.9，可以将 ω 0 = ω(z = 0) 测量到 Δω 0 = 0.5 的边际 1σ 误差。我们边缘化所有其他参数，包括 ω a ，其中状态方程根据比例因子 a 参数化为 w(a) = ω 0 + ω a (1- a)。为了获得更高的精度，需要进行大规模的光度红移测量，其中信号的最大增益来自于与中型星系团相对应的众多 ≈0 14 M ⊙ 晕。结合普朗克测量仪的预期结果，这种覆盖 10000 deg 2 至 Z m = 0.7 的近期五波段测量可以测量 ω 0 至 Δω 0 = 0.075 和 Δωa = 0.33。对在 Aw(zp) = 0.0298 的枢轴红移 z p = 0.27 处测量的 w 施加更强的组合约束。我们将几何测试与计划重子声振荡（BAO）和超新星Ia型实验测量的宇宙学和暗能量参数进行比较和结合，发现几何测试结果与由于不同简并性而导致的误差显着减少。几何透镜、CMB 和 BAO 实验的组合可以实现 Δω 0 = 0.047 和 Δωa = 0.111，在 z p = 0.62 时枢轴红移约束为 Δω(Z p ) = 0.020。提出了简单的关系，表明我们的透镜结果如何可以缩放到其他望远镜类别和测量参数。
We adapt the Jain-Taylor (2003) shear-ratio geometric lensing method to measure the dark energy equation of state, w = pv /ρv and its time derivative from dark matter haloes in cosmologies with arbitrary spatial curvature. The full shear-ratio covariance matrix is calculated for lensed sources, including the intervening large-scale structure and photometric redshift errors as additional sources of noise, and a maximum likelihood method for applying the test is presented. Decomposing the lensing matter distribution into dark matter haloes we calculate the parameter covariance matrix for an arbitrary experiment. Combining with the expected results from the cosmic microwave background (CMB) we design an optimal survey for probing dark energy. This shows that a targeted survey imaging 60 of the largest clusters in a hemisphere with five-band optical photometric redshifts to a median galaxy depth of Z m = 0.9 could measure ω 0 = ω(z = 0) to a marginal 1σ error of Δω 0 = 0.5. We marginalize over all other parameters including ω a , where the equation of state is parametrized in terms of scalefactor a as w(a) = ω 0 + ω a (1- a). For higher accuracy a large-scale photometric redshift survey is required, where the largest gain in signal arises from the numerous ≈0 14 M ⊙ haloes corresponding to medium-sized galaxy clusters. Combined with the expected Planck Surveyor results, such a near-future five-band survey covering 10000 deg 2 to Z m = 0.7 could measure ω 0 to Δω 0 = 0.075 and Δωa = 0.33. A stronger combined constraint is put on w measured at the pivot redshift z p = 0.27 of Aw(zp) = 0.0298. We compare and combine the geometric test with the cosmological and dark energy parameters measured from planned baryon acoustic oscillation (BAO) and supernova Type Ia experiments, and find that the geometric test results combine with a significant reduction in errors due to different degeneracies. A combination of geometric lensing, CMB and BAO experiments could achieve Δω 0 = 0.047 and Δωa = 0.111 with a pivot redshift constraint of Δω(Z p ) = 0.020 at z p = 0.62. Simple relations are presented that show how our lensing results can be scaled to other telescope classes and survey parameters.