Switched Magnetospheric Regulation of Pulsar Spin-Down

TLDR

Pulsars are famed for their rotational clock‑like stability and highly‑repeatable pulse shapes, yet unexplained deviations known as timing noise have long been observed. We consider the possibility that high‑precision monitoring of pulse profiles could lead to the formation of highly‑stable pulsar clocks. We show that timing behaviour often results from two distinct spin‑down rates, with pulsars switching abruptly between these states quasi‑periodically, and that for six pulsars the timing noise correlates with pulse‑shape changes, linking mode‑changing, nulling, intermittency, pulse‑shape variability and timing noise to magnetospheric changes.

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.