SIMBAD references

Improvements in ground-based advanced gravitational wave (GW) detectors may soon allow us to observe the GW signal of a nearby core-collapse supernova. For most progenitors, likely with slowly rotating cores, the dominant GW emission mechanisms are the post-bounce oscillations of the proto-neutron star (PNS) before the explosion. We present a new procedure to compute the eigenmodes of the system formed by the PNS and the stalled accretion shock in general relativity including space-time perturbations. We apply our analysis to two core-collapse simulations and show that our improved method is able to obtain eigenfrequencies that accurately match the features observed in the GW signal and to predict the qualitative behaviour of quasi-radial oscillations. Our analysis is possible thanks to a newly developed algorithm to classify the eigenmodes in different classes (f, p, and g modes), improving our previous results. We find that most of the GW energy is stored in the lowest-order eigenmodes, in particular in the ²g₁ mode and in the ²f mode. Our results also suggest that a low-frequency component of the GW signal attributed in previous works to the characteristic frequency of the standing accretion shock instability should be identified as the fundamental quadrupolar f mode. We also develop a formalism to estimate the contribution of quasi-radial (l = 0) modes to the GW quadrupolar component in a deformed background, with application to rapidly rotating cores. This work provides further support for asteroseismology of core-collapse supernovae and the inference of PNS properties based on GW observations.