Accuracy of neutron star radius measurement with the next generation of terrestrial gravitational-wave observatories
R. Huxford, Rahul Kashyap, Ssohrab Borhanian, Arnab Dhani, Ish Gupta, B. S. Sathyaprakash
Abstract
In this paper, we explore the prospect for improving the measurement accuracy of masses and radii of neutron stars. We consider imminent and long-term upgrades of the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo, as well as next-generation observatories---the Cosmic Explorer and Einstein Telescope. We find that neutron star radius with single events will be constrained to within roughly 500 m with the current generation of detectors and their upgrades. This will improve to 200, 100 and 50 m with a network of observatories that contain one, two or three next-generation observatories, respectively. Combining events in bins of $0.05{M}_{\ensuremath{\bigodot}}$ we find that for stiffer (softer) equations-of-state like ALF2 (APR4), a network of three XG observatories will determine the radius to within 30 m (100 m) over the entire mass range of neutron stars from $1{M}_{\ensuremath{\bigodot}}$ to $2.0{M}_{\ensuremath{\bigodot}}$ ($2.2{M}_{\ensuremath{\bigodot}}$), allowed by the respective equations-of-state. Neutron star masses will be measured to within 0.5% with three XG observatories irrespective of the actual equation-of-state. Measurement accuracies will be a factor of 4 or 2 worse if the network contains only one or two XG observatories, respectively, and a factor of 10 worse in the case of networks consisting of Advanced LIGO, Virgo KAGRA and their upgrades. Tens to hundreds of high-fidelity events detected by future observatories will allow us to accurately measure the mass-radius curve and hence determine the dense matter equation-of-state to exquisite precision.