Tidal deformability of neutron stars with realistic equations of state and their gravitational wave signatures in binary inspiral

TL;DR

This paper investigates how the tidal deformability parameter of neutron stars varies with different realistic equations of state and assesses the potential of gravitational wave detectors to distinguish these equations during binary inspirals.

Contribution

It provides calculations of tidal deformability for various equations of state and analyzes the detectability of these differences with current and future gravitational wave observatories.

Findings

Lambda spans an order of magnitude across models

Advanced LIGO can only detect stiff equations at 100 Mpc

Einstein Telescope can clearly observe tidal signatures

Abstract

The early part of the gravitational wave signal of binary neutron star inspirals can potentially yield robust information on the nuclear equation of state. The influence of a star's internal structure on the waveform is characterized by a single parameter: the tidal deformability lambda, which measures the star's quadrupole deformation in response to the companion's perturbing tidal field. We calculate lambda for a wide range of equations of state and find that the value of lambda spans an order of magnitude for the range of equation of state models considered. An analysis of the feasibility of discriminating between neutron star equations of state with gravitational wave observations of the early part of the inspiral reveals that the measurement error in lambda increases steeply with the total mass of the binary. Comparing the errors with the expected range of lambda, we find that Advanced LIGO observations of binaries at a distance of 100 Mpc will probe only unusually stiff equations of state, while the proposed Einstein Telescope is likely to see a clean tidal signature.