The role of mass, equation of state and superfluid reservoir in pulsar glitches

Observations of pulsar glitches provide useful insights on the internal physics of neutron stars: recent studies show how it is in principle possible to constrain pulsar masses from observations of their timing properties. We present a generalisation of a previous model for the rotational dynamics of pulsars, by examining the possibility of different extensions of the S-wave superfluid domain. The model allows to estimate the mass of 25 pulsars, satisfying appropriate observational conditions, from their largest glitch and average activity. The mass distribution of the sample is studied for different extensions of the superfluid domain, under the assumption of only crustal pinning. An inverse correlation between the amplitude of the largest glitch and pulsar's mass is found to hold in all cases, except that of crust-limited superfluidity. Reasonable values, within the range measured for neutron star masses, are obtained only if the superfluid domain extends for at least a small region inside the outer core, which is compatible with calculations of the neutron pairing gap; the mass estimates, moreover, stabilise when the domain extends to densities near the nuclear saturation. Future direct mass measurements of a few glitching pulsars have thus the potential to test the model and its input, providing indirect information on the microscopic properties of hadronic matter.