GLoW: novel methods for wave-optics phenomena in gravitational lensing

TL;DR

This paper introduces GLoW, a fast and accurate computational tool with novel methods for modeling wave-optics gravitational lensing phenomena, applicable to gravitational waves, radio bursts, and pulsars, aiding dark matter and large-scale structure studies.

Contribution

It presents new algorithms and approximations for wave-optics gravitational lensing, improving accuracy and speed over previous methods, and implements them in the GLoW software.

Findings

GLoW computes amplification factors in 1-10 milliseconds.

Specialized methods optimize symmetric and single-image lenses.

Approximations outperform existing solutions without losing accuracy.

Abstract

Wave-optics phenomena in gravitational lensing occur when the signal's wavelength is commensurate to the gravitational radius of the lens. Although potentially detectable in lensed gravitational waves, fast radio bursts and pulsars, accurate numerical predictions are challenging to compute. Here we present novel methods for wave-optics lensing that allow the treatment of general lenses. In addition to a general algorithm, specialized methods optimize symmetric lenses (arbitrary number of images) and generic lenses in the single-image regime. We also develop approximations for simple lenses (point-like and singular isothermal sphere) that drastically outperform known solutions without compromising accuracy. These algorithms are implemented in Gravitational Lensing of Waves (GLoW): an accurate, flexible, and fast code. GLoW efficiently computes the frequency-dependent amplification factor for generic lens models and arbitrary impact parameters in O(1 ms) to O(10 ms) depending on the lens configuration and complexity. GLoW is readily applicable to model lensing diffraction on gravitational-wave signals, offering new means to investigate the distribution of dark-matter and large-scale structure with signals from ground and space detectors.