Temporal Evolution of the Vela Pulsar's Pulse Profile

TL;DR

This study provides long-term observational data on the Vela pulsar, revealing pulse width variations, bright pulse rate changes, and potential cyclic patterns linked to precession, enhancing understanding of pulsar emission mechanisms.

Contribution

It offers extensive single pulse data and identifies cyclic pulse width changes possibly related to precession, a novel insight into pulsar behavior.

Findings

Pulse width varies over time with jumps after micro-glitches.

Bright pulse rates change after some micro-glitches.

Secular pulse width changes show possible cyclic periods matching X-ray periodicities.

Abstract

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.