The symmetry energy and incompressibility constrained by the observations of glitching pulsars

Abstract

We investigate the masses of glitching pulsars in order to constrain their equation of state (EOS). The observations of glitches (sudden jumps in rotational frequency) may provide information on the interior physics of neutron stars. With the assumption that glitches are triggered by superfluid neutrons, the masses of glitching neutron stars can be estimated using observations of maximum glitches. Together with the observations of thermal emission from glitching pulsars Vela and J1709–4429, the slope of symmetry energy and incompressibility of nuclear matter at saturation density can be constrained. The slope of symmetry energy L should be larger than 67 MeV while the lower limit of incompressibility for symmetric nuclear matter K0 is 215 MeV. We also obtain a relationship between L and K0: 6.173 MeV + 0.283 K0 ≤ L ≤ 7.729 MeV + 0.291 K0. The restricted EOSs are consistent with the observations of 2-solar-mass neutron stars and gravitational waves from a binary neutron star inspiral.