Modeling the complete gravitational wave spectrum of neutron star mergers

Abstract

In the context of neutron star mergers, we study the gravitational wave spectrum of the merger remnant using numerical relativity simulations. Postmerger spectra are characterized by a main peak frequency $f_2$ related to the particular structure and dynamics of the remnant hot hypermassive neutron star. We show that $f_2$ is correlated with the tidal coupling constant $\kappa^T_2$ that characterizes the binary tidal interactions during the late-inspiral--merger. The relation $f_2(\kappa^T_2)$ depends very weakly on the binary total mass, mass-ratio, equation of state, and thermal effects. This observation opens up the possibility of developing a model of the gravitational spectrum of every merger unifying the late-inspiral and postmerger descriptions.