Inferring the gravitational binding energy and moment of inertia of PSR J0030 + 0451 and PSR J0740 + 6620 from new universal relations

Abstract

The neutron star interior composition explorer (NICER) recently simultaneously measured the gravitational mass (M g) and radius (R) of PSR J0030 + 0451 and PSR J0740 + 6620, respectively. Inspired by the groundbreaking observations, we establish two high accuracy universal relations (with the relative error at 1% level) related to M g and R to infer the gravitational binding energy (BE) (E g) and moment of inertia (I) of the two pulsars. By combining these universal relations with the data of (M g, R) released by NICER collaboration, the gravitational BE and moment of inertia of PSR J0030 + 0451 can be constrained within and g cm2 at 68% credible level, respectively. The gravitational BE and moment of inertia of PSR J0740 + 6620 can be constrained within and g cm2 at 68% credible level, respectively.