The mechanisms of emission and changes in rotation frequency ('glitching') of
the Vela pulsar (J0835-4510) are not well understood. Further insight into
these mechanisms can be achieved by long-term studies of integrated pulse
width, timing residuals, and bright pulse rates. We have undertaken an
intensive observing campaign of Vela and collected over 6000 hours of single
pulse data. The data shows that the pulse width changes with time, including
marked jumps in width after micro-glitches (frequency changes). The abundance
of bright pulses also changes after some micro-glitches, but not all. The
secular changes in pulse width have three possible cyclic periods, that match
with X-ray periodicities of a helical jet that are interpreted as free
precession.Comment: 6 pages, 8 figures. Accepted for publication in The Astrophysical
Journa
