Universal relations applied to proto-neutron star generated gravitational waves from three-dimensional core collapse supernova simulations

Abstract

Using asteroseismology techniques, several relations have been developed that relate the quasi-normal, non-radial oscillation mode frequencies of the proto-neutron star (PNS) to the high frequency component of core collapse supernova (CCSN) generated gravitational waves predicted from simulation. These relations are universal in the sense that they are parameterized entirely by PNS properties, e.g., mean density or surface gravity, and are independent of both progenitor properties, e.g., zero age man sequence (ZAMS) mass or metallicity, and the physics included in CCSN simulations, e.g., nuclear equation of state (EOS). In this work, we apply several externally developed universal relations to PNS evolution data--specifically the mass, M, and radius, R,--generated from both two- and three-dimensional CCSN simulations and compare the resulting PNS oscillation frequencies predicted by the universal relations to the peak gravitational wave frequencies computed directly from the simulation-produced spectrogram. Additionally, we use the gravitational wave spectrogram peak frequencies as input to the universal relations and compare the predicted PNS properties from each relation to the true PNS properties as determined by the simulations. In this way, we show what these universal relations would predict for the PNS properties and their evolution from a real CCSN gravitational wave detection in the best case scenario, i.e., no detector noise. Our results indicate that caution must be exercised when using these universal relations, particularly when interpreting their predictions for PNS evolution from a gravitational wave detection, and that, given the extent to which we do see agreement between asteroseismological predictions and simulation outcomes, further development of universal relations would be beneficial.