Fast Fourier Transformation Based Evaluation of Microlensing Magnification with Extended Source

Abstract The extended source effect on microlensing magnification is nonnegligible and must be taken into account for an analysis of microlensing. However, the evaluation numerically expensive because it includes two-dimensional integral over profile. Various studies have developed methods to reduce this down one-dimensional-integral- or integral-free form, which adopt some approximations depend exact form profile, e.g., a disk linear/quadratic limb-darkening In paper, we develop new method evaluate based fast Fourier transformation (FFT), does not any applicable profiles. Our implementation FFT enables as ∼1 ms (CPU time laptop) guarantees accuracy better than 0.3%. can used template fitting huge data set light curves from existing upcoming surveys.