论文标题
快速多极方法用于重力镜头。应用高放大倍验微透明
Fast Multipole Method for Gravitational Lensing. Application to High Magnification Quasar Microlensing
论文作者
论文摘要
我们介绍了快速多极方法（FMM）的使用来加快重力透镜射线跟踪计算。当涉及大量偏转器$ n _*$时，该方法允许非常快速的射线偏转计算，同时对错误进行严格控制。特别是，我们将此方法与逆多边形映射技术（IPM）结合使用，以产生非常高的工作负载（高放大倍率，大尺寸和/或高分辨率）的微透镜放大贴图，这需要大量的转换器。使用FMM-IPM，对于标准逆射线拍摄，可以减少计算时间$ \ sim 10^5 $，从而在个人计算机上使用该算法，可与在GPU上使用标准IRS相当。我们还提供了一个灵活的Web界面，以便使用FMM-IPM \ footNote {http://gloton.ugr.es/microlensing/}轻松计算微透镜放大图。我们通过将其应用于一些挑战性有趣的天体物理场景，包括聚集的原始黑洞或靠近星系簇的巨大弧形的极其放大的恒星，来体现这种新方法的力量。我们还显示了FMM的性能/使用来计算由宇宙学模拟由大量元素（$ n \ gtrsim 10^7 $）组成的宇宙学仿真而产生的光环的性能/使用。
We introduce the use of the Fast Multipole Method (FMM) to speed up gravitational lensing ray tracing calculations. The method allows very fast calculation of ray deflections when a large number of deflectors, $N_*$, is involved, while keeping rigorous control on the errors. In particular, we apply this method, in combination with the Inverse Polygon Mapping technique (IPM), to quasar microlensing to generate microlensing magnification maps with very high workloads (high magnification, large size and/or high resolution) that require a very large number of deflectors. Using, FMM-IPM, the computation time can be reduced by a factor $\sim 10^5$ with respect to standard Inverse Ray Shooting, making the use of this algorithm on a personal computer comparable to the use of standard IRS on GPUs. We also provide a flexible web interface for easy calculation of microlensing magnification maps using FMM-IPM\footnote{http://gloton.ugr.es/microlensing/}. We exemplify the power of this new method by applying it to some challenging interesting astrophysical scenarios, including clustered primordial black holes, or extremely magnified stars close to the giant arcs of galaxy clusters. We also show the performance/use of FMM to calculate ray deflection for a halo resulting from cosmological simulations composed by a large number ($N\gtrsim 10^7$) of elements.
