The effect of Limber and flat-sky approximations on galaxy weak lensing
The effect of Limber and flat-sky approximations on galaxy weak lensing
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DOI：
10.1088/1475-7516/2017/05/014
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发表时间：
2017-04
影响因子：
6.4
通讯作者：
P. Lemos;A. Challinor;G. Efstathiou
中科院分区：
文献类型：
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作者：
P. Lemos;A. Challinor;G. Efstathiou
本文综述了常用的Limber近似和平天近似在计算星系弱透镜剪切功率谱和关联函数中的作用。这些近似在小尺度下是准确的，但最近有人声称，它们对低多极子的影响可能会导致从CFHTLenS等调查中推断的质量波动幅度增加，从而减少星系弱透镜效应与普朗克从宇宙微波背景观测中确定的幅度之间的紧张关系。在这里，我们探讨这些近似的宇宙学参数来自弱透镜调查的影响，使用CFHTLenS数据作为测试案例。我们的结论是，使用小角度近似的宇宙学参数估计是可以忽略不计的当前数据，并没有有助于当前的弱透镜调查和普朗克之间的紧张关系。
We review the effect of the commonly-used Limber and flat-sky approximations on the calculation of shear power spectra and correlation functions for galaxy weak lensing. These approximations are accurate at small scales, but it has been claimed recently that their impact on low multipoles could lead to an increase in the amplitude of the mass fluctuations inferred from surveys such as CFHTLenS, reducing the tension between galaxy weak lensing and the amplitude determined by Planck from observations of the cosmic microwave background. Here, we explore the impact of these approximations on cosmological parameters derived from weak lensing surveys, using the CFHTLenS data as a test case. We conclude that the use of small-angle approximations for cosmological parameter estimation is negligible for current data, and does not contribute to the tension between current weak lensing surveys and Planck.