Tidal deformability of neutron stars with realistic nuclear energy density functionals

Abstract

We investigate the constraints on the mass and radius of neutron stars by considering the tidal deformability in the merge of neutron star binaries. In order to extract the most reliable range of uncertainty from theory, we employ models based upon the Skyrme force and density functional theory and select models that are consistent with empirical data of finite nuclei, measured properties of nuclear matter around the saturation density, and observation of the maximum mass of neutron stars. From the selected models, we calculate the Love number $k_2$, dimensionless tidal deformability $\Lambda$, and mass-weighted deformability $\tilde{\Lambda}$ in the binary system. We find that all the models considered in this work give $\tilde{\Lambda}$ less than 800 which is the upper limit obtained from the measurement of GW170817. However, the model dependence of tidal deformability is manifest such that our results on the tidal deformability exhibit critical sensitivity to the size of neutron stars.