Lunch talk on Jun. 17, 2021

Cosmological Microlensing and Its Simulation Algorithm

Speaker:Wenwen Zheng (PMO)

Venue:SWIFAR Building 2111

Time:12:30 PM, Thursday, Jun. 17, 2021

Abstract:

Gravitational lensing studies about the deflection of light by matter, sometimes lensing effect can be strong enough to produce multiple-images. Cosmological microlensing is a regime that compact objects in lensing galaxies separate the multiple-images into unresolvable micro-images, and produce an uncorrelated brightness change with time in a single image of multiple images. The nature of cosmological microlensing improves our understanding of stellar mass functions and structures of quasars, but also brings errors to the measurement of Hubble constant. To achieve a better understanding of microlensing , accurate and efficient simulation will be needed. However, too many micro-lenses and micro-images makes it difficult to solve the lens equation directly, inverse ray-shooting is a widely used numerical method to obtain magnification patterns on source plane, but a direct approach of this method is quite a computationally expensive way . We present a inverse ray-shooting code accelerated by GPUs and interpolation algorithm to generate magnification patterns. The accuracy and speed of our code has reached a higher level, it is more than one order of magnitude faster than other GPU microlensing codes.

Report PPT:SWIFAR_Wenwen Zheng.pdf