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Most pulsars spin down at a steady rate, however the young pulsar PSR
B1828−11 has long been known to show correlated shape and spin-down
changes with timescales of roughly 500 and 250 days, perhaps
associated with large-scale magnetospheric switching. Stairs et
al. present multi-hour observations with the Parkes and Green Bank
Telescopes at multiple phases across the ∼500-day cycle and show that
the pulsar undergoes mode-changing between two stable, extreme profile
states. The fraction of time spent in each profile state, and the
variable rate of the mode transitions are directly related to the
spin-down changes. The image above shows the intensity as a function
of pulse phase and time/subintegration for a Parkes observation on
2000 March 30. The 10% of pulse phase surrounding the pulse is
displayed. Six transitions between wide (fainter) and narrow
(brighter) states can be readily identified. Full results are
published in
the paper published in
Monthly Notices of the Royal Astronomical Society.
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