Equation of State Independent Determination on the Radius of a 1.4 $M_{\odot }$ Neutron Star Using Mass-Radius Measurements

Abstract

Traditional methods for determining the radius of a 1.4 $M_{\odot }$ neutron star ($R_{1.4}$) rely on specific equations of state (EOS) models that describe various types of dense nuclear matter. This dependence on EOS models can introduce substantial systematic uncertainties, which may exceed the measurement uncertainties when constraining $R_{1.4}$. In this study, we explore a novel approach to constraining $R_{1.4}$ using data from NICER observations of PSR J0030+0451 (J0030) and PSR J0437-4715 (J0437). However, this work presents a more data-driven analysis framework, substantially decreasing the need for EOS assumptions. By analyzing the Mass-Radius measurements of these two neutron stars, we infer $R_{1.4}$ using statistical methods based mostly on observational data. We examine various hotspot configurations for J0030, along with new J0437 observations, and their effects on the inferred radius. Our results are consistent with X-ray timing, gravitational wave, and nuclear physics constraints, while avoiding EOS-related biases. The same method has also been applied to a simulated mass-radius dataset, based on our knowledge of future X-ray telescopes, demonstrating the model's ability to recover the injected $R_{1.4}$ value in certain cases. This method provides a data-driven pathway for extracting neutron star properties and offers a new approach for future observational efforts in neutron star astrophysics.

Published version in ApJ Letters

References in corpus (8)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• PSR J0030+0451 Mass and Radius from NICER Data and Implications for the Properties of Neutron Star Matter
• A NICER View of PSR J0030+0451: Millisecond Pulsar Parameter Estimation
• A NICER View of the Nearest and Brightest Millisecond Pulsar: PSR J0437$\unicode{x2013}$4715
• A NICER view of PSR J0030+0451: Implications for the dense matter equation of state
• Constraining the Neutron Star Mass-Radius Relation and Dense Matter Equation of State with NICER. II. Emission from Hot Spots on a Rapidly Rotating Neutron Star
• Constraining the dense matter equation of state with new NICER mass-radius measurements and new chiral effective field theory inputs
• CREX- and PREX-II-motivated relativistic interactions and their implications for the bulk properties of nuclear matter and neutron stars

Cited by in corpus (1)

• Model-Independent Determination of the Tidal Deformability of a 1.4 $M_{\odot }$ Neutron Star from Gravitational-Wave Measurements