Statistical Study of Neutron Star Glitches

Abstract

Neutron star glitches; spanning a period of 42 years of pulsar timing were studied. These glitches are from Radio, X-ray, Anomalous X-ray and Milliseconds Pulsars. Radio Pulsars dominates the glitch events, contributing 87% of the glitches. Pulsars of characteristic age bracket 103 to 105 yrs dominated the glitch events, at a rate of 5.2 glitches per year per pulsar. Pulsar of the above age bracket exhibits large size glitches compared to others. A large frequency spin-up (△v) is generally associated with large frequency derivative jump (△v ̇). The distribution of the glitch magnitude (△v/v) is bimodal reaffirming dual glitch mechanism, but that of spin-up (△v) is tending towards multi-modal. Moreover, glitches in Vela pulsar and PSR J0537-6910 showed strong elasticity of the objects, suggesting that the interiors of these objects are in thermal equilibrium. Glitches from PSR J1740-3015 and PSR J1341-6220 appeared to occur in groups, suggesting that their interior fluid is switching between two phases. We discussed the glitch activity of young pulsars in terms of vortex creep model.