The Gravitational Wave Signal from Core-collapse Supernovae

Abstract

We study gravitational waves(GWs)from a set of 2D multigroup neutrino radiation hydrodynamic simulations ofcore-collapse supernovae(CCSNe). Our goal is to systematize the current knowledge about the post-bounce CCSNGW signal and recognize the templatable features that could be used by the ground-based laser interferometers. Wedemonstrate that, starting from∼400 ms after core bounce, the dominant GW signal represents the fundamentalquadrupole(l=2)oscillation mode(f-mode)of the proto–neutron star(PNS), which can be accurately reproducedby a linear perturbation analysis of the angle-averaged PNS profile. Before that, in the time interval between∼200and∼400 ms after bounce, the dominant mode has two radial nodes and represents ag-mode. We associate thehigh-frequency noise in the GW spectrograms above the main signal withp-modes, while below the dominantfrequency there is a region with very little power. The collection of models presented here summarizes thedependence of the CCSN GW signal on the progenitor mass, equation of state, many-body corrections to theneutrino opacity, and rotation. Weak dependence of the dominant GW frequency on the progenitor mass motivatesus to provide a simplefit for it as a function of time, which can be used as a prior when looking for CCSNcandidates in the LIGO data.