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arXiv 0806.0937astro-ph
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测光重子声学振荡和弱透镜测量的距离、增长因子和暗能量约束

Distance, Growth Factor, and Dark Energy Constraints from Photometric Baryon Acoustic Oscillation and Weak Lensing Measurements

Hu Zhan, Lloyd Knox, J. Anthony Tyson

摘要:

重子声学振荡(BAO)和弱透镜(WL)是宇宙学的互补探测。我们探讨了从光度计BAO和WL技术的距离和增长因子的测量和调查的作用,限制暗能量的距离和增长因子。我们发现WL的增长因子对暗能量约束有很大的影响,但远不如距离强大。从WL的暗能量约束集中在相当少的距离本征模比那些从BAO,与最大的贡献,是敏感的绝对距离的模式。这两种技术都有一些确定的距离本征模是不是很敏感的暗能量状态方程参数w_0和w_a,这表明它们可以容纳额外的参数暗能量和控制系统的不确定性。BAO和WL的联合分析远比单独使用任何一种技术更强大,由此产生的对距离和增长因子的限制将有助于区分暗能量和修改的引力模型。大型综合巡天望远镜(LSST)将在数十亿个星系的样本上产生WL和角BAO。在普朗克的宇宙微波背景先验条件下,联合LSST BAO和WL对红移0.3和3之间的10个log(1+z)均匀分布的同动距离可以获得0.5%的精度。另外,由于在Friedmann-Robertson-Walker度规解中,直接影响观测量的角直径距离仅通过曲率半径与共动距离联系在一起,因此LSST可以在对共动距离进行约束的同时,对宇宙的平均曲率参数Omega_k进行0.017的纯度规约束.

英文摘要:

Baryon acoustic oscillations (BAOs) and weak lensing (WL) are complementary probes of cosmology. We explore the distance and growth factor measurements from photometric BAO and WL techniques and investigate the roles of the distance and growth factor in constraining dark energy. We find for WL that the growth factor has a great impact on dark energy constraints but is much less powerful than the distance. Dark energy constraints from WL are concentrated in considerably fewer distance eigenmodes than those from BAO, with the largest contributions from modes that are sensitive to the absolute distance. Both techniques have some well determined distance eigenmodes that are not very sensitive to the dark energy equation of state parameters w_0 and w_a, suggesting that they can accommodate additional parameters for dark energy and for the control of systematic uncertainties. A joint analysis of BAO and WL is far more powerful than either technique alone, and the resulting constraints on the distance and growth factor will be useful for distinguishing dark energy and modified gravity models. The Large Synoptic Survey Telescope (LSST) will yield both WL and angular BAO over a sample of several billion galaxies. Joint LSST BAO and WL can yield 0.5% level precision on ten comoving distances evenly spaced in log(1+z) between redshift 0.3 and 3 with cosmic microwave background priors from Planck. In addition, since the angular diameter distance, which directly affects the observables, is linked to the comoving distance solely by the curvature radius in the Friedmann-Robertson-Walker metric solution, LSST can achieve a pure metric constraint of 0.017 on the mean curvature parameter Omega_k of the universe simultaneously with the constraints on the comoving distances.

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