Independent discovery of a nulling pulsar with unusual sub-pulse drifting properties with the Murchison Widefield Array

TL;DR

This paper reports the discovery of a nulling pulsar with unusual sub-pulse drifting behaviors using the Murchison Widefield Array, demonstrating the survey's effectiveness in detecting intermittent pulsars and providing insights into pulsar emission models.

Contribution

The paper presents the first independent discovery of PSR J0027-1956 with detailed analysis of its nulling and sub-pulse drifting properties, showcasing the MWA survey's capabilities.

Findings

Pulsar has a ~77% nulling fraction.

Exhibits complex sub-pulse drifting with mode switching.

Drift rate evolution often interrupted at specific phases.

Abstract

We report the independent discovery of PSR J0027-1956 with the Murchison Widefield Array (MWA) in the ongoing Southern-sky MWA Rapid Two-meter (SMART) pulsar survey. J0027-1956 has a period of ~1.306 s, a dispersion measure (DM) of ~20.869 pc cm^-3 , and a nulling fraction of ~77%. This pulsar highlights the advantages of the survey's long dwell times (~80 min), which, when fully searched, will be sensitive to the expected population of similarly bright, intermittent pulsars with long nulls. A single-pulse analysis in the MWA's 140-170 MHz band also reveals a complex sub-pulse drifting behavior, including both rapid changes of the drift rate characteristic of mode switching pulsars, as well as a slow, consistent evolution of the drift rate within modes. In some longer drift sequences, interruptions in the otherwise smooth drift rate evolution occur preferentially at a particular phase, typically lasting a few pulses. These properties make this pulsar an ideal test bed for prevailing models of drifting behavior such as the carousel model.