Long-term rotational and emission variability of 17 radio pulsars. Issue 4 (29th April 2022)

• Record Type: Journal Article
• Authors: Shaw, B; Stappers, B W; Weltevrede, P; Brook, P R; Karastergiou, A; Jordan, C A; Keith, M J; Kramer, M; Lyne, A G
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 513:Issue 4(2022)
• Page Start: 5861
• Page End: 5880
• Publication Date: 2022-04-29
• Subjects: methods: analytical -- methods: data analysis -- methods: statistical -- stars: neutron -- pulsars: general; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stac1156
• Languages: English
• ISSNs: 0035-8711

Abstract

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.