Speaker
Description
The lensing of Gravitational Waves (GWs) due to intervening matter distribution in the universe can lead to chromatic signatures in the wave-optics limit. The reliance of the lens mass distribution modelling makes detection of lensed GWs challenging. Hence to detect lensed GWs in a model-independent way, we develop the wave-optics lensing search technique called mu-GLANCE and deploy it on the GW events observed up to the fourth observation catalog GWTC-4 of LIGO-Virgo-KAGRA. The method tests residual strain for correlated features across the detector network via cross-correlation and infers lensing-induced modulations with a Bayesian framework as a double-check. The unmodelled search picks up one plausible candidate GW190408 with a 3.1 sigma deviation from pure detector noise. However, exploring the wave-optics lensing modulation signatures on this event, we do not find any conclusive evidence of the wave-optics feature at 95% confidence level. We also test the recently discovered gravitational wave event, GW231123, known for its massive black hole components. It is hypothesized to be gravitationally lensed, but our analysis finds no strong evidence for its lensing, with a signal varying from 1.4 sigma to 7.2 sigma across various waveform models. However, we find that waveform systematics for such heavy binary systems are sufficiently large to shadow the lensing signatures in short-duration signals (0.2s) like GW231123, preventing any definitive claim of lensing at this stage. We confidently rule out the presence of any statistically significant wave-optics lensing signal in the events up to GWTC-4.
| Other topic / keywords: | Wave-optics lensing, Gravitational waves, Gravitational waves: sources |
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