基于Shapelets基函数的引力透镜质量重构方法

引力透镜效应是探测星系团物质分布的有效方法之一.目前,利用引力透镜数据重构星系团质量分布的主流方法可以分为两大类,即参数法和非参数法.在实际研究工作中,受限于质量模型假设和计算分辨率等方面的影响,现有的重构算法仍有诸多亟需解决的问题.基于Shapelets基函数的引力透镜质量重构方法通过基函数来实现引力透镜质量重构,使用Shapelets基函数分解引力透镜势,以引力透镜中多重像的位置和背景星系椭率畸变为限制条件来迭代求解基函数系数从而得到透镜体的质量分布.通过拟合一个模拟的NFW (Navarro,Frenk and White)透镜系统测试了新方法的可行性,结果表明新方法可以在整体上重构出透镜体的质量分布,并拟合出接近真实的源位置,能够为星系团质量测量提供一套灵活且高效的重构算法.

Gravitational Lensing Mass Reconstruction Method Based on Shapelets Basis Functions

The gravitational lensing effect is one of the most effective probes for detecting the distribution of mass in galaxy clusters. To date, the methods of gravitational lensing mass reconstructions can be divided into two categories, parametric methods and non-parametric methods. However, due to the model assumptions and computational resolution, the available reconstruction methods still have a number of problems that need to be solved. The method of gravitational lens mass reconstruction based on Shapelets basis function is used to reconstruct the gravitational lens mass. The Shapelets basis function is used to decompose the gravitational lens potential, and the basis function coefficients are iteratively calculated by the constraints of the multiple image position and the background galaxy ellipticity distortion of gravitational lensing. The new method is validated by fitting the mock data from NFW (Navarro, Frenk and White) lensing model. The results show the gravitational lensing mass distribution can be reconstructed reasonably by our new method and the source position can be calculated accurately. Our new method provides a flexible and efficient method for gravitational lensing mass reconstruction.