Determining the Structure of Rotating Massive Stellar Cores with Gravitational Waves

TL;DR

This paper introduces a new method to analyze gravitational wave signals from rotating stellar core collapses, aiming to predict supernova properties before shock breakout by correlating GW features with progenitor core characteristics.

Contribution

The study develops a novel analysis technique that uses early GW signals to constrain the progenitor star's core compactness and angular momentum prior to explosion.

Findings

GW features correlate with progenitor compactness and rotation.

The method can predict supernova properties before shock breakout.

Analysis of simulations supports the predictive capability of GW signals.

Abstract

The gravitational wave (GW) signal resulting from stellar core collapse encodes a wealth of information about the physical parameters of the progenitor star and the resulting core-collapse supernova (CCSN). We present a novel approach to constrain CCSN progenitor properties at collapse using two of the most detectable parts of the GW signal: the core-bounce signal and evolution of the dominant frequency mode from the protoneutron star. We focus on the period after core bounce but before explosion and investigate the predictive power of GWs from rotating CCSNe to constrain properties of the progenitor star. We analyze 34 2D and four 3D neutrinoradiation-hydrodynamic simulations of stellar core collapse in progenitors of varied initial mass and rotation rate. Extending previous work, we verify the compactness of the progenitor at collapse to correlate with the early ramp-up slope, and in rotating cases, also with the core angular momentum. Combining this information with the bounce signal, we present a new analysis method to constrain the pre-collapse core compactness of the progenitor. Because these GW features occur less than a second after core bounce, this analysis could allow astronomers to predict electromagnetic properties of a resulting CCSN even before shock breakout.