Glitches as Probes of Neutron Star Interiors

In several young pulsars, the steady slow-down in rotation rate as they lose kinetic energy is occasionally interrupted by a sudden small increase in rotation rate, followed by a recovery which is often closely exponential in its form. This recovery provides strong evidence for the existence of a fluid component inside the neutron star. This fluid can be identified with superfluid neutrons in the inner part of the stellar crust. Detailed studies of the phenomenon can give information on the amount of fluid present, on the physics of the outward flow of angular momentum as the pulsar slows down, what causes the glitches and why some pulsars show much more glitch activity than others.