A new parameter space study of cosmological microlensing

TL;DR

This study uses GPU-accelerated simulations to generate a comprehensive set of microlensing magnification maps across various parameters, aiding future analysis of lensed quasars from upcoming surveys.

Contribution

It provides a large grid of 2550 microlensing maps across parameter space, demonstrating that single maps can often represent average behaviors, which is valuable for future survey analyses.

Findings

Most parameter space regions are well-represented by a single map.

Random microlens positions have limited impact on map properties.

The study offers a resource for analyzing future lensed quasar observations.

Abstract

Cosmological gravitational microlensing is a useful technique for understanding the structure of the inner parts of a quasar, especially the accretion disk and the central supermassive black hole. So far, most of the cosmological microlensing studies have focused on single objects from ~90 currently known lensed quasars. However, present and planned all-sky surveys are expected to discover thousands of new lensed systems. Using a graphics processing unit (GPU) accelerated ray-shooting code, we have generated 2550 magnification maps uniformly across the convergence ({\kappa}) and shear ({\gamma}) parameter space of interest to microlensing. We examine the effect of random realizations of the microlens positions on map properties such as the magnification probability distribution (MPD). It is shown that for most of the parameter space a single map is representative of an average behaviour. All of the simulations have been carried out on the GPU-Supercomputer for Theoretical Astrophysics Research (gSTAR).