The Thousand-Pulsar-Array programme on MeerKAT XIX: Single-pulse data analysis, nulling and pulse energy distributions

Abstract

We present the Thousand Pulsar Array (TPA) single-pulse data set, obtained with the MeerKAT radio telescope and comprising time-series observations of 1192 pulsars, typically containing ~1000 consecutive pulses per source. We describe the MeerTime Single Pulse software pipeline which calibrates the data and automatically excises interference signals to produce data products suitable for typical single-pulse studies. To demonstrate the capabilities of the dataset, we carry out a population-level study of phase-averaged single-pulse energy distributions and nulling behaviour. Pulse energy distributions are modelled within a Bayesian framework choosing from a range of intrinsic energy distributions, and including an explicit nulling fraction. We find that approximately half of the pulsars require multi-component intrinsic energy distributions, while the remainder are consistent with single-component models. Nulling is detected or constrained for most pulsars in the sample, and both the occurrence and inferred nulling fraction show systematic variation across the P-$\dot{P}$ diagram. In particular, nulling fractions increase with spin period and exhibit only a weak dependence on period derivative. We also examine trends in the preferred forms of pulse energy distributions as a function of spin-down luminosity, finding modest evidence for population-level evolution. Estimates of single-pulse luminosities indicate that individual pulses can exceed the long-term average luminosity by large factors, particularly for low-$\dot{E}$ pulsars. These results characterise the statistical properties of single-pulse emission across a large pulsar sample and highlight the limitations of phase-averaged energy distributions for capturing the full complexity of pulsar emission variability.