Timing Behavior of the Magnetically Active Rotation - Powered Pulsar in the Supernova Remnant Kesteven 75

We report a large spin-up glitch in PSR J1846−0258 which coincided with the onset of magnetar-like behavior on 2006 May 31. We show that the pulsar experienced an unusually large glitch recovery, with a recovery fraction of Q = 5.9 ± 0.3, resulting in a net decrease of the pulse frequency. Such a glitch recovery has never before been observed in a rotation-powered pulsar, however, similar but smaller glitch over-recovery has been recently reported in the magnetar AXP 4U 0142+61 and may have occurred in the SGR 1900+14. We discuss the implications of the unusual timing behavior in PSR J1846−0258 on its status as the first identified magnetically active rotation-powered pulsar. Subject headings: pulsars: general—pulsars: individual (PSR J1846−0258)—Xrays: stars