A Realistic Projection for Constraining the Neutron Star Equation of State with the LIGO–Virgo–KAGRA Detector Network in the A+ Era

Abstract The upcoming A+ era of the LIGO–Virgo–KAGRA network—featuring upgrades to Advanced LIGO (aLIGO+) and Advanced Virgo (AdV+)—will enable more frequent and precise observations of binary neutron star (BNS) mergers, improving the constraints on the neutron star equation of state (EOS). In this study, we applied reduced-order quadrature techniques for full parameter estimation of 3000 simulated gravitational-wave signals from BNS mergers at A+ sensitivity following three EOS models: hqc18 , sly230a , and mpa1 . We found a systematic trend in the recovery of tidal deformability, with overestimation at higher component masses and underestimation at lower masses. Postprocessing of the inferred parameters reveals the impact of these biases on EOS constraints. We quantified these effects and proposed correction strategies to improve EOS inference. This timely framework is well suited for deployment in the upcoming A+ observing runs.