Limitations in constraining neutron star radii and nuclear properties from inspiral gravitational wave detections

TL;DR

This study assesses how well third-generation gravitational wave detectors can constrain neutron star properties and the EoS, revealing limitations due to low-mass neutron star scarcity and degeneracies in nuclear parameters.

Contribution

It demonstrates the potential and limitations of GW observations in constraining the neutron star EoS and nuclear properties, emphasizing the need for additional observational methods.

Findings

EoS can be tightly constrained at densities 1-4 times nuclear saturation density

Constraints on the EoS at sub-saturation densities are weak due to low-mass neutron star scarcity

Nuclear properties are degenerate in their effects on the EoS, complicating constraints

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. Assuming an optimistic binary neutron star (BNS) merger rate, we generate synthetic 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 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 note that the nuclear properties are degenerate in their influence on the EoS, making 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.