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...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.展开更多
We present an empirical investigation of 14 real world networks, which can be described by bipartite graphs. We show that the basic elements （the actor nodes） in all the networks cooperate and compete in some acts ...We present an empirical investigation of 14 real world networks, which can be described by bipartite graphs. We show that the basic elements （the actor nodes） in all the networks cooperate and compete in some acts （activities, organizations, or events）. Each node is assigned by a ＇node weight＇, which denotes the obtained competition result. We are interested in the distribution and disparity of the node weight and propose three parameters for the description. Firstly, empirically we observe that the total node weight distributions of all the systems may be fitted by the so-called ＇shifted power law＇ function form. The key parameters of the function, a and -γ can be used to describe the disparity. Secondly, a ＇node weight disparity＇, γ, is defined for the same purpose. The empirical relationships among the parameters γ, γ and γ, are obtained. From the relationships between γ and a as well as Y and % one can deduce the relationship between γ and % which is in a good agreement with the empirically obtained relationship. The results show that the node weight distribution is very uneven.展开更多
文摘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.
基金Supported by the National Natural Science Foundation of China under grant Nos 10635040 and 70671089.
文摘We present an empirical investigation of 14 real world networks, which can be described by bipartite graphs. We show that the basic elements （the actor nodes） in all the networks cooperate and compete in some acts （activities, organizations, or events）. Each node is assigned by a ＇node weight＇, which denotes the obtained competition result. We are interested in the distribution and disparity of the node weight and propose three parameters for the description. Firstly, empirically we observe that the total node weight distributions of all the systems may be fitted by the so-called ＇shifted power law＇ function form. The key parameters of the function, a and -γ can be used to describe the disparity. Secondly, a ＇node weight disparity＇, γ, is defined for the same purpose. The empirical relationships among the parameters γ, γ and γ, are obtained. From the relationships between γ and a as well as Y and % one can deduce the relationship between γ and % which is in a good agreement with the empirically obtained relationship. The results show that the node weight distribution is very uneven.
