English

Measuring glitch recoveries and braking indices with Bayesian model selection

High Energy Astrophysical Phenomena 2024-07-10 v1

Abstract

For a selection of 35 pulsars with large spin-up glitches (Δν/ν106\Delta{\nu}/\nu\geq10^{-6}), which are monitored by the Jodrell Bank Observatory, we analyse 157 glitches and their recoveries. All parameters are measured consistently and we choose the best model to describe the post-glitch recovery based on Bayesian evidence. We present updated glitch epochs, sizes, changes of spin down rate, exponentially recovering components (amplitude and corresponding timescale) when present, as well as pulsars' second frequency derivatives and their glitch associated changes if detected. We discuss the different observed styles of post-glitch recovery as well as some particularly interesting sources. Several correlations are revealed between glitch parameters and pulsar spin parameters, including a very strong correlation between a pulsar's interglitch ν¨|\ddot{\nu}| and ν˙\dot{\nu}, as well as between the glitch-induced spin-down rate change Δν˙p\Delta\dot{\nu}_{\rm p} that does not relax exponentially and ν˙\dot{\nu}. We find that the ratio Δν˙p/ν¨\left|\Delta \dot{\nu}_{\mathrm{p}}/\ddot{\nu}\right| can be used as an estimate of glitch recurrence times, especially for those pulsars for which there are indications of a characteristic glitch size and interglitch waiting time. We calculate the interglitch braking index nn and find that pulsars with large glitches typically have nn greater than 33, suggesting that internal torques dominate the rotational evolution between glitches. The external torque, e.g. from electromagnetic dipole radiation, could dominate the observed ν¨\ddot{\nu} for the youngest pulsars (104  yr\lesssim10^{4}\;\mathrm{yr}), which may be expected to display n3n\sim3.

Keywords

Cite

@article{arxiv.2406.09219,
  title  = {Measuring glitch recoveries and braking indices with Bayesian model selection},
  author = {Yang Liu and Michael J. Keith and Danai Antonopoulou and Patrick Weltevrede and Benjamin Shaw and Benjamin W. Stappers and Andrew G. Lyne and Mitchell B. Mickaliger and Avishek Basu},
  journal= {arXiv preprint arXiv:2406.09219},
  year   = {2024}
}

Comments

24 pages, 14 figures, 8 tables. Accepted for publication in MNRAS