| Name: Aniruddha Chakraborty |
| Affiliation: Tata Institute of Fundamental Research, Mumbai |
| Conference ID: ASI2026_871 |
| Title: Identification of Wave-optics Lensed Gravitational Waves with Residual Cross-correlation |
| Abstract Type: Poster |
| Abstract Category: Galaxies and Cosmology |
| Author(s) and Co-Author(s) with Affiliation: Aniruddha Chakraborty(TIFR Mumbai), Suvodip Mukherjee(TIFR Mumbai) |
| Abstract: The lensing of Gravitational Waves (GWs) due to intervening matter distribution in the universe can lead to chromatic signatures in the wave-optics limit. This makes it challenging to model for the mass distribution of the lens and hence requires a model-free lensing detection technique from GW data. Thus we develop the first model-independent wave-optics lensing search technique 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. These unmodelled searches pick up one plausible candidate GW190408 with a slightly above threshold residual amplitude compared to the residual expected from detector noise. However, exploring the wave-optics lensing modulation signatures on this event, we do not find any conclusive evidence of the wave-optics lensing signal in the data. The recently discovered gravitational wave event, GW231123, known for its massive black hole components is hypothesized to be gravitationally lensed. However, our analysis finds no strong evidence for lensing in GW231123, but reveals a potential residual feature that could be consistent with wave-optics lensing. However, we find that waveform systematics for such heavy binary systems are sufficiently large to shadow the lensing signatures in short-duration signals 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. |
