On the identification of individual gravitational wave image types of a lensed system using higher-order modes

TL;DR

This paper demonstrates that higher-order modes in gravitational waves can be used to identify individual lensed image types, enabling unambiguous confirmation of gravitational lensing events with current detector networks.

Contribution

It introduces a method to utilize higher-order modes for distinguishing lensed gravitational wave images, improving analysis accuracy and confirming lensing.

Findings

Higher-order modes enable identification of individual lensed image types.

Analysis of higher-order modes improves accuracy in lensed gravitational wave events.

Method facilitates unambiguous confirmation of gravitational lensing in GW detections.

Abstract

Similarly to light, gravitational waves can be gravitationally lensed as they propagate near massive astrophysical objects such as galaxies, stars, or black holes. In recent years, forecasts have suggested a reasonable chance of strong gravitational-wave lensing detections with the LIGO-Virgo-KAGRA detector network at design sensitivity. As a consequence, methods to analyse lensed detections have seen rapid development. However, the impact of higher-order modes on the lensing analyses is still under investigation. In this work, we show that the presence of higher-order modes enables the identification of the individual images types for the observed gravitational wave events when two lensed images are detected, which would lead to unambiguous confirmation of lensing. In addition, we show that higher-order mode content can be analyzed more accurately with strongly lensed gravitational wave events.