Inferring neutron star properties from GW170817 with universal relations
Abstract
Because all neutron stars share a common equation of state, tidal deformability constraints from the compact binary coalescence GW170817 have implications for the properties of neutron stars in other systems. Using equationofstate insensitive relations between macroscopic observables like moment of inertia (I ), tidal deformability (Λ ) and stellar compactness, we derive constraints on these properties as a function of neutron star mass based on the LIGOVirgo Collaboration's canonical deformability measurement, Λ_{1.4}=19 0_{120}^{+390}. Specific estimates of Λ , I , dimensionless spin χ , and stellar radius R for a few systems targeted by radio or xray studies are extracted from the general constraints. We also infer the canonical neutron star radius as R_{1.4}=10.9_{1.5}^{+1.9} km at 90% confidence. We further demonstrate how a gravitationalwave measurement of Λ_{1.4} can be combined with independent measurements of neutron star radii to tighten constraints on the tidal deformability as a proxy for the equation of state. We find that GW170817 and existing observations of six thermonuclear bursters in lowmass xray binaries jointly imply Λ_{1.4}=19 6_{63}^{+92} at the 90% confidence level.
 Publication:

Physical Review D
 Pub Date:
 June 2019
 DOI:
 10.1103/PhysRevD.99.123026
 arXiv:
 arXiv:1902.04557
 Bibcode:
 2019PhRvD..99l3026K
 Keywords:

 General Relativity and Quantum Cosmology;
 Astrophysics  High Energy Astrophysical Phenomena;
 Nuclear Theory
 EPrint:
 18 pages, 7 figures