标题： 宇宙背景中的结构引起的引力透镜效应 显示英文标题

标题： Gravitational Lensing by a structure in a cosmological background

摘要： 我们使用基于LTB度规的FRW宇宙学背景中的精确广义相对论模型结构，来研究宇宙学和动态结构的引力透镜效应。 通过求解测地线方程，使用不同的密度剖面对该模型结构的偏转角和通过引力透镜的时间延迟进行了研究。 这些精确计算的结果已与薄透镜近似进行了比较。 我们证明了基于修改后的NFW密度剖面并在过渡到FRW背景之前存在空洞的薄透镜近似结果与精确的广义相对论计算非常吻合。 然而，基于正常NFW剖面的薄透镜近似与精确的相对论计算有所不同。 结构越不致密，差异越大。 我们还研究了我们的计算对强透镜情况下弧的观测解释以及弱透镜情况下剪切减小的影响。 在现有数据中未发现显著差异。 显示英文摘要

摘要： We use an exact general relativistic model structure within an FRW cosmological background based on a LTB metric to study the gravitational lensing by a cosmological and dynamical structure. Using different density profiles for the model structure, the deviation angle and the time delay through the gravitational lensing has been studied by solving the geodesic equations. The results of these exact calculations have been compared to the thin lens approximation. We have shown that the result for the thin lens approximation based on a modified NFW density profile with a void before going over to the FRW background matches very well with the exact general relativistic calculations. However, the thin lens approximation based on a normal NFW profile does differ from the exact relativistic calculation. The difference is more the less compact the structure is. We have also looked at the impact of our calculation on the observational interpretation of arcs in the case of strong lensing and also the reduced shear in the case of weak lensing. No significant difference has been seen in the data available.