Full-sky lensing shear at second order
Full-sky lensing shear at second order
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二阶全天透镜剪切
DOI：
10.1103/physrevd.81.083002
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发表时间：
2009
影响因子：
5
通讯作者：
F. Vernizzi
中科院分区：
文献类型：
--
作者：
F. Bernardeau;C. Bonvin;F. Vernizzi
我们在不依赖小角度或薄透镜近似的情况下计算了引力势中高达二阶的简化宇宙剪切力。这是通过求解萨克斯方程获得的，该方程描述了光学极限下光束的无穷小横截面的变形，并将星系的固有形状映射到它们的角度图像中。计算是在泊松规中完成的，没有特定的物质含量，包括二阶生成的矢量和张量扰动，并考虑了固定红移源平面的不均匀性。我们的最终结果以球体上的 spin-2 算子表示，并且在整个天空上有效。除了在小角度尺度上占主导地位的著名的透镜-透镜和玻恩校正之外，我们还发现了新的非线性耦合。这些是纯粹的广义相对论本征贡献，源处的引力势与透镜之间的耦合，透镜的时间延迟之间的耦合以及两个光子偏转之间的耦合，以及由于二阶矢量和张量分量引起的非线性耦合。光源红移的不均匀性引起光子红移与透镜之间的耦合。所有这些校正在大角度尺度上变得很重要，因此在全天或部分全天巡天中计算高阶可观测值（例如双谱）时应将其包括在内。
We compute the reduced cosmic shear up to second order in the gravitational potential without relying on the small-angle or thin-lens approximation. This is obtained by solving the Sachs equation which describes the deformation of the infinitesimal cross section of a light bundle in the optical limit, and maps galaxy intrinsic shapes into their angular images. The calculation is done in the Poisson gauge without a specific matter content, including vector and tensor perturbations generated at second order and taking account of the inhomogeneities of a fixed redshift source plane. Our final result is expressed in terms of spin-2 operators on the sphere and is valid on the full sky. Beside the well-known lens-lens and Born corrections that dominate on small angular scales, we find new nonlinear couplings. These are a purely general relativistic intrinsic contribution, a coupling between the gravitational potential at the source with the lens, couplings between the time delay with the lens and between two photon deflections, as well as nonlinear couplings due to the second-order vector and tensor components. The inhomogeneity in the redshift of the source induces a coupling between the photon redshift with the lens. All these corrections become important on large angular scales and should thus be included when computing higher-order observables such as the bispectrum, in full or partially full-sky surveys.
影响因子：
6.5
作者：
S. Hilbert;J. Hartlap;S. White;P. Schneider
通讯作者：
S. Hilbert;J. Hartlap;S. White;P. Schneider