Rotation of the neutron-drip superfluid in pulsars - The interaction and pinning of vortices

The movement and pinning of neutron vortices has been studied with reference to the superfluid component whose relaxation gives the large discontinuities in angular velocity time-derivative observed for PSR 0355 + 54 and 0833 - 45. At high temperatures, early in the life of a pulsar, the vortices are not pinned but move in almost exact corotation with the superfluid. The balance of evidence indicates that corotation of vortices and superfluid, which has consequences for the interpretation of timing noise and the estimation of internal temperatures, persists throughout the life of a pulsar.