Long-term rotational and emission variability of 17 radio pulsars
Abstract
With the ever-increasing sensitivity and timing baselines of modern radio telescopes, a growing number of pulsars are being shown to exhibit transitions in their rotational and radio emission properties. In many of these cases, the two are correlated with pulsars assuming a unique spin-down rate ($\dot{\nu }$) for each of their specific emission states. In this work, we revisit 17 radio pulsars previously shown to exhibit spin-down rate variations. Using a Gaussian process regression (GPR) method to model the timing residuals and the evolution of the profile shape, we confirm the transitions already observed and reveal new transitions in 8 yr of extended monitoring with greater time resolution and enhanced observing bandwidth. We confirm that seven of these sources show emission-correlated $\dot{\nu }$ transitions ($\Delta \dot{\nu }$), and we characterize this correlation for one additional pulsar, PSR B1642-03. We demonstrate that GPR is able to reveal extremely subtle profile variations given sufficient data quality. We also corroborate the dependence of $\Delta \dot{\nu }$ amplitude on $\dot{\nu }$ and pulsar characteristic age. Linking $\Delta \dot{\nu }$ to changes in the global magnetospheric charge density Δρ, we speculate that $\dot{\nu }$ transitions associated with large Δρ values may be exhibiting detectable profile changes with improved data quality, in cases where they have not previously been observed.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 2022
- DOI:
- 10.1093/mnras/stac1156
- arXiv:
- arXiv:2204.10767
- Bibcode:
- 2022MNRAS.513.5861S
- Keywords:
-
- methods: analytical;
- methods: data analysis;
- methods: statistical;
- stars: neutron;
- pulsars: general;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 20 pages, 16 figures, 3 tables