The big glitcher: The rotation history of PSR J0537-6910

We report the results of an extensive monitoring campaign of PSR J0537 - 6910, the 16 ms pulsar in the Large Magellanic Cloud, using data acquired with the Rossi X-Ray Timing Explorer. The spin evolution of this pulsar is found to experience extreme episodic discontinuities in its spin-down rate during the 2.6 yr campaign. The rate of occurrence of these timing glitches is 2.3 per year, comparable to the highest seen for any pulsar. The mean glitch amplitude produced a fractional change in the frequency of Deltanu/nu = 0.36 x 10(-6) and in the frequency derivative of Delta(nu) over dot/(nu) over dot = 3 x 10(-4). Despite this prodigious timing activity, we are able to derive a phase-connected timing solution between glitch events with an average spin-down rate of - 1.9743 x 10(-10) Hz s(-1). The integrated effect of the glitches in. (nu) over dot was so large that the apparent characteristic age of the pulsar (-nu/2(nu) over dot) decreased significantly during the campaign. We discuss the implications of a large glitch activity and high braking index on the spin evolution of young pulsars.