基于坐标变换的引力透镜模拟

Simulation of gravitational lensing based on coordinate transformation

光线在引力场中会发生偏折是广义相对论理论所预言的现象之一.而引力透镜效应则是指,当观测者与背景光源之间存在较大质量的前景天体时,大质量天体的引力场使背景光源发出光线的传播方向发生改变而导致的一系列观测效应,在天体物理、宇宙学等方向的研究中具有重要意义.本文主要介绍了基于坐标变换的引力透镜模拟,对于前景天体考虑了两种透镜模型,并推导了相应的透镜方程及光线偏折角表达式.然后对于同一类透镜模型下背景光源三种不同的表面亮度分布进行研究,通过计算机生成了相应的引力透镜成像结果.

The deflection of light in the gravitational field is one of the predictions of the general theory of relativity.The gravitational lensing effect refers to a series of observation effects caused by the bending of light emitted by the light source due to the gravitational field of the massive object between the distant light source and the observer,which is of great importance in the research of astrophysics,cosmology and other fields.In this paper,the simulation of gravitational lensing based on coordinate transformation is mainly introduced.Two lens models are considered for the foreground lens,and the corresponding lens equation and the expression of deflection angle are presented.Then we discuss three different surface brightness profiles of the background light source under the same lens model,and the corresponding lensed images are generated by computer.