利用数值模拟方法对类星体-星系团引力透镜成因的再考察

A Further Investigation on the Quasar Cluster Associations with Numerical Simulations

利用星系团形成的数值模拟技术所得到的星系团以及大尺度结构，本文研究了星系团和其周围环境物质的引力透镜效应对背景类星体计数的影响，以期解释最近观测到的类星体星系团成协现象．然而，得到的结果却是：用星系团及所遵循的大尺度结构的引力透镜效应，不能解释所观测到的类星体数密度．这与解析方法所得结论一致．分析表明：目前所观测到的类星体与星系团成协，如果不是统计涨落，则无法用引力透镜效应来解释。

Using the simulated clusters of galaxies and large scale structures of the universe with a flat cosmological model Ω 0 + λ 0= 1 , we study the effect of gravitational bias by clusters and their environmental matter on the number density of distant radio bright quasars around foreground clusters. It is shown that the gravitational lensing magnification by clusters alone or combined with the large scale structures cannot account for the large amplitude of the radio quasar overdensity behind clusters on scale of 10 arcminutes, in consistent with both the analytic and simulating results for the optically selected quasars. We conclude that the recently detected quasar cluster associations, if real , are unlikely due to the magnification bias.