A Study of Single Pulses in the Parkes Multibeam Pulsar Survey

TL;DR

This study reprocessed the Parkes Multibeam Pulsar Survey data to analyze single-pulse properties, revealing that most pulsars' pulse amplitudes are better modeled by a power-law divided by an exponential, and suggesting a common emission mechanism for pulsars and RRATs.

Contribution

It introduces a new analysis of single-pulse amplitude distributions using novel fitting functions and compares pulsar and RRAT pulse properties to explore their emission mechanisms.

Findings

Most pulsars' pulse amplitudes fit a power-law divided by an exponential.

A correlation exists between the single-pulse S/N ratio and pulsar spin period.

Pulsars and RRATs show similar pulse-energy distributions, indicating a possible common emission mechanism.

Abstract

We reprocessed the Parkes Multibeam Pulsar Survey, searching for single pulses out to a DM of 5000 pc cm$^{-3}$ with widths of up to one second. We recorded single pulses from 264 known pulsars and 14 Rotating Radio Transients. We produced amplitude distributions for each pulsar which we fit with log-normal distributions, power-law tails, and a power-law function divided by an exponential function, finding that some pulsars show a deviation from a log-normal distribution in the form of an excess of high-energy pulses. We found that a function consisting of a power-law divided by an exponential fit the distributions of most pulsars better than either log-normal or power-law functions. For pulsars that were detected in a periodicity search, we computed the ratio of their single-pulse signal-to-noise ratios to their signal-to-noise ratios from a Fourier transform and looked for correlations between this ratio and physical parameters of the pulsars. The only correlation found is the expected relationship between this ratio and the spin period. Fitting log-normal distributions to the amplitudes of pulses from RRATs showed similar behaviour for most RRATs. Here, however, there seem to be two distinct distributions of pulses, with the lower-energy distribution being consistent with noise. Pulse-energy distributions for two of the RRATS processed were consistent with those found for normal pulsars, suggesting that pulsars and RRATs have a common emission mechanism, but other factors influence the specific emission properties of each source class.