High Time Resolution Observations of the January 2000 Glitch in the Vela Pulsar

Pulsars are rotating neutron stars, sweeping the emission regions from the magnetic poles across our line of sight. Isolated neutron stars lose angular momentum through dipole radiation and (possibly) particle winds; hence, they slow down extremely steadily, making them among the most reliable timing sources available. However, it is well known that younger pulsars can suffer glitches, when they suddenly deviate from their stable rotation period. On 2000 January 16 (MJD 51,559), the rate of pulsation from the Vela pulsar (B0833-45) showed such a fractional period change of 3.1 × 10 -6, the largest recorded for this pulsar. The glitch was detected and reported by the Hobart radio telescope. The speedy announcement allowed the X-ray telescope, Chandra, and others to make Target-of-Opportunity observations. The data placed an upper limit of 40 s for the transition time from the original to the new period. Four relaxation timescales are found, which are believed to be due to the variable coupling between the crust and the interior fluid. One is very short, about 60 s; the others have been previously reported and are 0.56, 3.33, and 19.1 days in length.