The Thousand-Pulsar-Array programme on MeerKAT XVII: Discovery of beating radio emission variability in PSR J1514-4834

TL;DR

This paper analyzes complex subpulse modulation in PSR J1514-4834, revealing coexistence of drifting subpulses and amplitude modulation, explained by a beat system, and introduces a new methodology for studying pulsar emission dynamics.

Contribution

It presents a novel phase correlation methodology and demonstrates that a beat system explains the complex modulation patterns in PSR J1514-4834, differing from carousel models.

Findings

Coexistence of multiple periodicities in pulsar emission.

Development of a new 2D Fourier Transform phase correlation method.

Identification of a beat system causing complex subpulse behavior.

Abstract

We present a comprehensive analysis of the complex subpulse modulation patterns in PSR J1514-4834 (B1510-48) using L-band data from the Thousand-Pulsar-Array (TPA) programme, complemented with further MeerKAT UHF-band data. We demonstrate that periodic drifting subpulses and rapid amplitude modulation with a period of about 2 pulse periods coexist. It is established that these two periodic emission patterns interfere in the form of a beat system, giving rise to multiple spectral features. We develop a new methodology which confirms the expected correlations in the complex phase of the beat features in a 2D Fourier Transform of the data. Therefore, a relatively simple beat system can explain the complex single-pulse behaviour of this pulsar. The simultaneous coexistence of multiple subpulse modulation periodicities is rare in the population and points to poorly understood intricate dynamics within pulsar magnetospheres. A comparison with PSR B0943+10 is made, for which the coexistence of multiple periodicities has been argued to be a natural consequence of a rotating carousel. However, our observations of PSR J1514-4834 require a different explanation, involving time-delayed interactions between separate regions of the magnetosphere. The developed phase correlation methodology opens up the route for underlying beat systems in the modulation patterns of more pulsars.