标题： 球面弱透镜效应 显示英文标题

标题： Weak Lensing On the Celestial Sphere

摘要： 本文详细描述了由宇宙中大尺度非均匀性引起的引力透镜效应在整个天空中造成的星系图像扭曲模式。 我们提出了一种张量球谐函数形式来描述这种模式，并给出了许多有用的公式。 将其应用于密度非均匀性时，我们计算了畸变图案的角功率谱以及由于有限星系采样和宇宙学起伏引起的噪声特性。 我们表明，对于非常近处的星系（$z\simlt0.2$），存在可检测到的剪切水平。 对于如此浅薄的样本，大部分最大的信噪比来自非常大的角尺度（$\theta\simgt10^\circ$），尽管它以非常小的剪切水平（$\simlt10^{-3}$）的形式出现。 显示英文摘要

摘要： This paper details a description of the pattern of galaxy image distortion over the entire sky caused by the gravitational lensing which is the result of large scale inhomogeneities in our universe. We present a tensor spherical harmonic formalism to describe this pattern, giving many useful formulae. This is applied to density inhomogeneities, where we compute the angular power spectrum of the shear pattern, as well as the noise properties due to finite galaxy sampling and cosmic variance. We show that a detectable level of shear is present for very nearby galaxies, $z\simlt0.2$. For such a shallow sample much of the largest signal-to-noise comes from very large angular scales, $\theta\simgt10^\circ$, although it is in the form of very small shear at a level $\simlt10^{-3}$.