基于小波方法的平滑算法在引力透镜中的应用  

A New Smoothing Algorithm and its Application in Gravitational Lensing

作　　者：杨毅彬[1,2] 李国亮[3] Alessandro B. Romeo 

机构地区：[1]中国科学技术大学天体物理中心,合肥230026 [2]中国科学院紫金山天文台,南京210008 [3]中国科学院上海天文台,上海200030 [4]Onsala Space Observatory,Chalmers University of Technology,SE-43992 Onsala,Sweden

出　　处：《天文学报》2008年第4期359-369,共11页Acta Astronomica Sinica

摘　　要：基于离散小波变换(DWT)方法,提出了一种可用于计算三维数值模拟样本面密度的平滑算法.为检验方法的有效性,利用该算法研究了两组不同质量解析度的引力透镜数值模拟样本,样本采用了暗物质晕的等温椭球模型,使用蒙特卡罗方法生成.计算结果表明此算法能够在很高的精度上构建引力透镜模拟样本的面密度分布轮廓,由面密度计算出来的透镜的临界曲线和焦散曲线也能较好地和理论曲线吻合,结果是令人满意的.同时比较了三组不同的小波基的计算结果,包括Daub4,Daub6和B-spline 3th,给出了最优的选择.在不损失平滑效果的同时,此算法具有非常高的速度,非常适合于处理以后更高精度的N体数值模拟.We develop a new smoothing algorithm for computing surface densities from 3D numerical simulation samples. This algorithm is based on DWT （discrete wavelet transform） method. We test the algorithm by applying it to two gravitational lensing simulation samples which are generated by monte-carlo method and have different mass resolution, the results show our algorithm can successfully reconstruct the surface density of lens. We also compute the critical curves and caustics of lens samples, the results show that they can fit the theoretic curves very well. We test three different wavelet bases and compare them, including Daub4, Daub6 and B-spline 3th. Our algorithm is very fast and is suitable for high resolution N-body simulations.

关 键 词：物理数据与过程 引力透镜 方法 数值 

分 类 号：P134[天文地球—天体力学]