Modeling Core-Collapse Supernovae Gravitational-Wave Memory in Laser Interferometric Data

TL;DR

This paper analyzes low-frequency gravitational wave emissions, especially the linear memory effect, from core-collapse supernovae, providing models and recommendations for detecting these signals in interferometric data.

Contribution

It introduces semi-analytical models linking supernova shock dynamics to GW memory and discusses methods to improve signal analysis considering simulation limitations.

Findings

GW memory amplitude depends on observer position and supernova dynamics.

Proposed models relate shock motion to GW memory strength.

Recommendations for angular sampling improve multi-observer averaging.

Abstract

We study the properties of the gravitational wave (GW) emission between $10^{-5}$ Hz and $50$ Hz (which we refer to as low-frequency emission) from core-collapse supernovae, in the context of studying such signals in laser interferometric data as well as performing multi-messenger astronomy. We pay particular attention to the GW linear memory, which is when the signal amplitude does not return to zero after the GW burst. Based on the long term simulation of a core-collapse supernova of a solar-metallicity star with a zero-age main sequence mass of 15 solar masses, we discuss the spectral properties, the memory's dependence on observer position and the polarization of low-frequency GWs from slowly non (or slowly) rotating core-collapse supernovae. We make recommendations on the angular spacing of the orientations needed to properly produce results that are averaged over multiple observer locations by investigating the angular dependence of the GW emission. We propose semi-analytical models that quantify the relationship between the bulk motion of the supernova shock-wave and the GW memory amplitude. We discuss how to extend neutrino generated GW signals from numerical simulations that were terminated before the neutrino emission has subsided. We discuss how the premature halt of simulations and the non-zero amplitude of the GW memory can induce artefacts during the data analysis process. Lastly, we also investigate potential solutions and issues in the use of taperings for both ground and space-based interferometers.