Neutron star equation of state and tidal deformability with nuclear energy density functionals

Neutron star physics is the ultimate testing place for the physics of dense nuclear matter. Before the detection of gravitational waves from the merger of binary neutron stars, various nuclear equations of state have been used to estimate the macroscopic properties of neutron stars, such as masses and radii, based on electromagnetic observations. However, recent observations of the tidal deformability of neutron star from the gravitational waves GW170817 opened a new era of multi-messenger astronomy and astrophysics, and much theoretical work has been devoted to estimating the tidal deformability of neutron stars. In this article, we review our recent work on the application of nuclear energy density functionals to the properties of neutron stars, including tidal deformability. We found that many nuclear energy density functionals, including the new KIDS (Korea: IBS-Daegu-Sungkyunkwan) model, satisfy constraints both from current electromagnetic and from gravitational-wave observations. We discuss future possibilities of constraining the nuclear matter equation of state from ground-based experiments and multi-messenger observations.