Gravelamps: Gravitational Wave Lensing Mass Profile Model Selection

TL;DR

Gravelamps is a software package that analyzes lensed gravitational wave signals to determine the lensing mass profile, supporting both microlensing and macrolensing scenarios with wave optics and geometric optics models.

Contribution

The paper introduces Gravelamps, a new tool for gravitational wave lensing analysis that integrates parameter estimation and model selection for various lensing regimes.

Findings

Successfully analyzed simulated microlensing and macrolensing events.

Demonstrated capability for parameter estimation and model selection.

Applied to GW170809, found no strong lensing evidence.

Abstract

We present the package Gravelamps which is designed to analyse lensed gravitational wave signals in order to constrain the mass density profile of the lensing object. Gravelamps does this via parameter estimation using the framework of bilby, which enables estimation of both the lens and the source parameters. The package can be used to study both microlensing and macrolensing cases -- where the lensing mass distribution is described by a point mass and extended mass density profile respectively -- and allows the user to easily and freely switch between the full wave optics and approximate geometric optics description. The performance of Gravelamps is demonstrated via simulated analysis of both mircolensing and macrolensing events, illustrating its capability for both parameter estimation and model selection in the wave optics and hybrid environments. To further demonstrate the utility of the package, the real gravitational-wave event GW170809 was analysed using Gravelamps; this event was found to yield no strong evidence supporting the lensing hypothesis, consistent with previously published results.