Joint Bayesian inference of gravitational-wave and NICER data

We perform a joint, multi-messenger analysis of the neutron star equation of state by combining the gravitational-wave measurements of GW170817 with the measurements made by the Neutron Star Interior Composition Explorer (NICER) of PSR J0030+0451 and PSR J0740+6620. We develop a joint likelihood function that can simultaneously sample in the parameter space of the gravitational-wave and X-ray measurements. We incorporate models of the equation of state generated using chiral effective field theory into the joint GW/X-ray analysis. We sample the likelihood in equation of state and mass, which provides a direct measurement of chiral field theory equation of state.