RXTE/HEXTE ANALYSIS OF THE CRAB PULSAR GLITCH OF 2000 JULY

Abstract

Hard X-ray data from the RXTE observatory (HEXTE energy range 15–240 keV) have been analyzed to obtain a phase-coherent timing solution for the Crab pulsar glitch of 2000 July 15. The results are: (1) the step change in the rotation frequency of the Crab pulsar at the epoch of the glitch is ; (2) the step change in its time derivative is ; and (3) the timescale of decay of the step change is days. The first two results are consistent with those obtained at radio frequencies by the Jodrell Bank observatory. The last result has not been quoted in the literature, but could be an underestimate due to a lack of observations very close to the glitch epoch. Through comparison with the monthly timing ephemeris published by the Jodrell group for the Crab pulsar, the time delay between the main peaks of the hard X-ray and radio pulse profiles is estimated to be +411 ± 167 μs. Although this number is not very significant, it is consistent with the number derived for the 2–16 keV energy range, using the Proportional Counter Array instrument of RXTE. The separation between the two peaks of the integrated pulse profile of the Crab pulsar and the ratio of their intensities are both statistically similar before and after the glitch. The dead time corrected integrated photon flux within the integrated pulse profile appears to decrease after the glitch, although this is not a statistically strong result. This work achieves what can be considered to be an almost absolute timing analysis of the Crab pulsar hard X-ray data.