Can we distinguish millilensed GWs from precessing GW signals?

One of the key characteristics of millilensed gravitational wave (GW) waveform shapes is the frequency-dependent beating pattern formed by the overlapping of individual millilensed signals. Interestingly, a similar beating pattern in the GW waveform can also occur from precessing binary black hole systems.

The apparent similarity between the waveforms of the two different signal origins can pose challenges in correctly identifying the underlying physical effects. In this project (Liu & Kim, 2024), we to explore our ability to distinguish between these two types of binary black hole signals, in the context of the current LIGO-Virgo-KAGRA detector network, by (a) computing SNRs obtained with different templates, (b) performing a parameter estimation (PE) study of lensed and processing GWs.