弱引力透镜是宇宙学的重要探针之一，是理解宇宙大尺度结构和几何的主要工具。弱引力透镜信号包含了暗物质、暗能量和宇宙学尺度上引力的本质等基础物理的信息，因此是暗能量巡天的主要科学目标之一。第三代暗能量巡天项目已经给出了可靠的弱引力透镜信号测量，其中也指出了若干存在的系统误差效应。在精确宇宙学框架下的第四代暗能量巡天将达到超越1%的测量精度，因此这些1%-10%量级的系统误差都必须得到正确的处理。本项目拟基于数值模拟和弱引力透镜模拟天图、模拟星系场的构建技术，针对弱引力透镜在精确宇宙学框架下理论上和观测中面临的若干重要问题进行研究。研究内容包括源-透镜成团效应、重子物理对高阶透镜信号的影响和快速模拟天图生成方法等理论上系统误差的研究，也包括观测中星系内禀指向污染修正方法、测光红移误差修正方法和通过测量星系成团性中的宇宙学放大效应提取弱引力透镜信号方法的研究。

As a major probe of the modern cosmology, weak gravitational lensing is an important tool to study the large-scale structure and geometry of our Universe. Weak lensing signal contains valuable information of fundamental physics, such as dark matter, dark energy and the nature of gravity at cosmological scales. Thus, the measurement of weak lensing signal is a major goal of dark energy projects. The lensing signal has been robustly measured by the stage III dark energy projects, and meanwhile, several systematics are realized to be important. In precision cosmology era, the planned stage IV surveys will achieve 1% or better precision. Thus, these systematics of order 1%-10% must be treated carefully. Based on the technique of simulation and lensing mock construction, this project is aiming at these important problems in the weak lensing cosmology, including the systematics in theoretical modelling such as source-lens clustering effect, baryonic impacts on the high-order lensing signal, fast mock generation methods, and also the problems in observational aspect, such as the calibration of intrinsic alignment contamination, correction of photo-z scatter error and lensing signal extraction from counting galaxies.