Understanding supernova gravitational waves with protoneutron star asteroseismology

TL;DR

This paper explores the relationship between protoneutron-star oscillation frequencies and gravitational wave signals from supernovae to improve understanding and extraction of physical properties despite model dependencies.

Contribution

It systematically examines asteroseismology of protoneutron stars and compares oscillation frequencies with simulated gravitational wave signals to identify universal relations.

Findings

Identified potential universal relations between gravitational waves and physical properties.

Compared linear analysis of protoneutron-star oscillations with simulation data.

Highlighted the importance of model-independent features for gravitational wave analysis.

Abstract

Supernovae are one of the most promising gravitational wave sources. But, since the system of the supernovae is nearly spherically symmetric, the expected gravitational waves from them are relatively weak, compared to the case of the compact binary mergers. Thus, at least using the current gravitational wave detectors, only the gravitational waves from a supernova that occurred in our galaxy could be detected. To reliably extract information from gravitational waves originating from such a low event rate, thorough preparation is essential. However, because supernova gravitational waves strongly depend on model parameters, such as progenitor mass and the equation of state for dense matter, it may be difficult to extract physical properties even if the gravitational waves are detected. The universal relations between gravitational-wave signals and physical properties, independent of model parameters, are important for solving this difficulty. To discuss such a universal relation, in this article, we systematically examine the protoneutron-star oscillation frequencies with the linear analysis, the so-called asteroseismology, and compare them with the gravitational wave signals in the simulations.