Postglitch Relaxation of the VELA Pulsar after Its First Eight Large Glitches: A Reevaluation with the Vortex Creep Model

We present a comprehensive reevaluation of eight of the nine glitches observed to date from the Vela pulsar, and the postglitch relaxation following each glitch. All glitch data sets can be described in terms of three distinct components of short and intermediate time scale exponential relaxation, followed by a long-term recovery of the glitch-induced change in the spin-down rate that is linear in t, ΔΩ˙ c (t)∞t. We interpret the short and the intermediate time scale exponential relaxation, characterized by relaxation times of 10 hr, 3 d .2, and 32 d as the linear response of vortex creep in those regions of the pinned superfluid in the neutron star crust through which no sudden vortex motion occurred at the time of the glitch