Stochastic Nature of Gravitational Waves from Supernova Explosions with Standing Accretion Shock Instability

TL;DR

This paper investigates the stochastic gravitational wave signals from supernova explosions driven by SASI, revealing their spectrum peaks near 100 Hz and potential detectability by LIGO for Galactic events.

Contribution

It provides the first 3D simulation-based analysis of gravitational waves from SASI-driven supernovae, emphasizing the stochastic nature of waveforms and their spectral features.

Findings

Waveforms are highly stochastic due to chaotic SASI development.

Spectral peak near 100 Hz linked to SASI-induced matter overturns.

Potential detectability of signals by LIGO-class detectors for Galactic supernovae.

Abstract

We study properties of gravitational waves based on the three-dimensional simulations, which demonstrate the neutrino-driven explosions aided by the standing accretion shock instability (SASI). Pushed by evidence supporting slow rotation prior to core-collapse, we focus on the asphericities in neutrino emissions and matter motions outside the protoneutron star. By performing a ray-tracing calculation in 3D, we estimate accurately the gravitational waveforms from anisotropic neutrino emissions. In contrast to the previous work assuming axisymmetry, we find that the gravitational waveforms vary much more stochastically because the explosion anisotropies depend sensitively on the growth of the SASI which develops chaotically in all directions. Our results show that the gravitational-wave spectrum has its peak near $\sim 100$ Hz, reflecting the SASI-induced matter overturns of $\sim O(10)$ ms. We point out that the detection of such signals, possibly visible to the LIGO-class detectors for a Galactic supernova, could be an important probe into the long-veiled explosion mechanism.