Switched magnetospheric regulation of pulsar spin-down

TL;DR

This paper reveals that pulsar timing noise and pulse shape variability are caused by abrupt switches between different magnetospheric states, linking various pulsar phenomena and suggesting potential for more stable pulsar clocks.

Contribution

It demonstrates that pulsar spin-down and pulse shape changes are driven by magnetospheric state switches, unifying multiple pulsar phenomena and offering new insights into pulsar timing noise.

Findings

Timing noise correlates with pulse shape changes in six pulsars.

Pulsars switch abruptly between two spin-down states.

Magnetospheric changes cause mode-changing, nulling, and intermittency.

Abstract

Pulsars are famed for their rotational clock-like stability and their highly-repeatable pulse shapes. However, it has long been known that there are unexplained deviations (often termed "timing noise") from the rate at which we predict these clocks should run. We show that timing behaviour often results from typically two different spin-down rates. Pulsars switch abruptly between these states, often quasi-periodically, leading to the observed spin-down patterns. We show that for six pulsars the timing noise is correlated with changes in the pulse shape. Many pulsar phenomena including mode-changing, nulling, intermittency, pulse shape variability and timing noise are therefore linked and caused by changes in the pulsar's magnetosphere. We consider the possibility that high-precision monitoring of pulse profiles could lead to the formation of highly-stable pulsar clocks.