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

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 identification of lensing. In addition, we show that we can analyse higher-order-mode content with greater accuracy with strongly lensed gravitational wave events.