The Thousand-Pulsar-Array programme on MeerKAT: -- VI. Pulse widths of a large and diverse sample of radio pulsars

Abstract

We present pulse width measurements for a sample of radio pulsars observed with the MeerKAT telescope as part of the Thousand-Pulsar-Array (TPA) programme in the MeerTime project. For a centre frequency of 1284 MHz, we obtain 762 $W_{10}$ measurements across the total bandwidth of 775 MHz, where $W_{10}$ is the width at the 10% level of the pulse peak. We also measure about 400 $W_{10}$ values in each of the four or eight frequency sub-bands. Assuming, the width is a function of the rotation period P, this relationship can be described with a power law with power law index $\mu =-0.29\pm 0.03$. However, using orthogonal distance regression, we determine a steeper power law with $\mu =-0.63\pm 0.06$. A density plot of the period-width data reveals such a fit to align well with the contours of highest density. Building on a previous population synthesis model, we obtain population-based estimates of the obliquity of the magnetic axis with respect to the rotation axis for our pulsars. Investigating the width changes over frequency, we unambiguously identify a group of pulsars that have width broadening at higher frequencies. The measured width changes show a monotonic behaviour with frequency for the whole TPA pulsar population, whether the pulses are becoming narrower or broader with increasing frequency. We exclude a sensitivity bias, scattering and noticeable differences in the pulse component numbers as explanations for these width changes, and attempt an explanation using a qualitative model of five contributing Gaussian pulse components with flux density spectra that depend on their rotational phase.

Accepted for publication in MNRAS. 20 pages, 19 figures, 7 tables

References in corpus (20)

• TEMPO2, a new pulsar timing package. I: Overview
• Tempo2, a new pulsar timing package. II: The timing model and precision estimates
• Switched magnetospheric regulation of pulsar spin-down
• The MeerKAT Telescope as a Pulsar Facility: System verification and early science results from MeerTime
• Pulsar braking and the P-Pdot diagram
• Pulsar polarisation below 200 MHz: Average profiles and propagation effects
• The population of pulsars with interpulses and the implications for beam evolution
• Multi-frequency integrated profiles of pulsars
• Constraints on viewing geometries from radio observations of $\gamma$-ray-loud pulsars using a novel method
• A Fan Beam Model for Radio Pulsars. I. Observational Evidence
• The Thousand-Pulsar-Array programme on MeerKAT I: Science objectives and first results
• Meterwavelength Single-pulse Polarimetric Emission Survey
• The Period-Width relationship for radio pulsars revisited
• Frequency dependence of pulse width for 150 radio normal pulsars
• On the difference between gamma-ray-detected and non-gamma-ray-detected pulsars
• Mapping the magnetosphere of PSR B1055-52
• 5 GHz TMRT observations of 71 pulsars
• The Galactic population and properties of young, highly-energetic pulsars
• TMRT observations of 26 pulsars at 8.6 GHz
• Meterwavelength Single-pulse Polarimetric Emission Survey. V. Flux density, component spectral variation and emission states

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