Neutron Star Crustal Plate Tectonics. III. Cracking, Glitches, and Gamma-Ray Bursts

When the growing vortex pinning stresses in a cool, spinning-down superfluid neutron star strain the crust beyond its elastic yield strength, large-scale crust cracking events may occur. These would result in pulsar timing glitches with magnitude and recurrence rates near those observed. In old or dead radio pulsars these sudden releases of stored elastic energy should give bursts of X-ray and gamma-rays whose number, energy, and rise time suggest those of the so far unidentified gamma-ray burst sources. The surface magnetic field of a spinning-down crust-cracking neutron star breaks up into large surface patches (platelets) which move apart from each other. Each platelet retains its original surface magnetic field, while the expanding new interplatelet crust regions have little or none. Pulsar spin-down torque observations would reflect the decrease in average surface dipole field, while the field strength inferred from a cyclotron resonance spectral feature above a platelet would remain high and independent of stellar age.