Limitations in constraining neutron star radii and nuclear properties from inspiral gravitational wave detections
Year: 2026
Type: article
Abstract: We investigate the constraints on the neutron star equation of state (EoS) and nuclear properties achievable with third-generation gravitational wave detectors using the Fisher information matrix approach within the relativistic mean field (RMF) theory. Assuming an optimistic binary neutron star (BNS) merger rate, we generate simulated inspiral gravitational wave (GW) signals corresponding to one year of observation. From these simulated data, we compute the covariance matrix and posterior distributions for nuclear properties and EoS. Our results show that the EoS can be tightly constrained, particularly in the density range between one and four times nuclear saturation density. However, due to the scarcity of low-mass neutron stars in the GW sample, the EoS at sub-saturation densities remains poorly constrained. Thus, in turn, leads to weaker constraints on neutron star radii, as the radii are sensitive to the low-density EoS. Additionally, we present the expected correlations among nuclear parameters in general and plots of the inferred symmetry energy in particular, which represent degeneracies in their influence on the EoS and make them difficult to be constrained through GW observations alone. These highlights inherent limitations of inspiral GW signals in probing dense matter properties. Therefore, precise radius measurements, post-merger GW observations, and supplementary constraints from terrestrial nuclear experiments remain essential for a comprehensive understanding of dense matter.
DOI: 10.1103/f166-khyg
Authors: Zhenyu Zhu, Richard O’Shaughnessy
Institution: Rochester Institute of Technology
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: National Science Foundation
Awards: The Operation and Maintenance of the Laser Interferometer Gravitational Wave Observatory (LIGO), Explorations of Extreme and Eccentric Binary Black Hole Mergers, The Construction of the Advanced Laser Interferometer Gravitational Wave Observatory (AdvLIGO), Collaborative Research: WoU-MMA Constraining the nuclear equation of state and population of neutron star mergers through observations of transient and persistent phenomena, WoU-MMA: Inference About Gravitational Wave Sources and Source Populations in the Era of Perpetual Discovery
OpenAlex ID: W4414459782
