JPL pulsar timing observations - Spinups in PSR 0525+21

Observations of the very slow objects PSR 0525+21, in which two small spin-ups occur, are presented. Twelve years of observation at 2.4 GHz reveal that the ratio of small jumps to the period is about one billionth, where the period is about 3.745 s; the analysis that arrived at these results is shown. The short-term behavior following the larger jump suggests an exponential decay, and long-term changes in the period derivative of about 0.03 percent clearly persist after each jump. It is argued that the spin-ups are not due to starquakes, but may be caused by uncoupling of a lighter crust from the core.