Gravitational Lensing of Core Collapse Supernova Gravitational Wave Signals

TL;DR

This paper proposes a new power spectrum analysis technique to identify and characterize gravitational lensing effects on gravitational wave signals from core-collapse supernovae, especially for nearby sources detectable by ground-based detectors.

Contribution

It introduces a novel method based on power spectrum peak association to detect and estimate lens masses in lensed GW signals from supernovae.

Findings

Differentiates lensed and unlensed signals for lens masses >150 solar masses

Can detect lensing effects for lenses as small as 15 solar masses

Enables lens mass estimation from the GW signal

Abstract

We discuss the prospects of gravitational lensing of gravitational waves (GWs) coming from core-collapse supernovae (CCSN). As the CCSN GW signal can only be detected from within our own Galaxy and the local group by current and upcoming ground-based GW detectors, we focus on microlensing. We introduce a new technique based on analysis of the power spectrum and association of peaks of the power spectrum with the peaks of the amplification factor to identify lensed signals. We validate our method by applying it on the CCSN-like mock signals lensed by a point mass lens. We find that the lensed and unlensed signal can be differentiated using the association of peaks by more than one sigma for lens masses M$_{\rm L} {>} 150{\rm M}_{\odot}$. We also study the correlation integral between the power spectra and corresponding amplification factor. This statistical approach is able to differentiate between unlensed and lensed signals for lenses as small as M$_{\rm L} {\sim} 15{\rm M}_{\odot}$. Further, we demonstrate that this method can be used to estimate the mass of a lens in case the signal is lensed. The power spectrum based analysis is general and can be applied to any broad band signal and is especially useful for incoherent signals.