RRATs: New Discoveries, Timing Solutions & Musings

TL;DR

This paper reports new discoveries and timing solutions for RRATs, explores their neutron star characteristics, and discusses whether they form a distinct neutron star population, emphasizing the utility of single-pulse searches.

Contribution

Provides seven new coherent timing solutions for RRATs, discovers seven new transient sources including a potential extragalactic one, and analyzes their properties to understand their nature.

Findings

Seven new timing solutions for RRATs.

Discovery of seven new transient sources, one possibly extragalactic.

RRATs are likely not a separate population but a detection label influenced by selection effects.

Abstract

We describe observations of Rotating RAdio Transients (RRATs) that were discovered in a re-analysis of the Parkes Multi-beam Pulsar Survey (PMPS). The sources have now been monitored for sufficiently long to obtain seven new coherent timing solutions, to make a total of 14 now known. Furthermore we announce the discovery of 7 new transient sources, one of which may be extragalactic in origin (with $z\sim0.1$) and would then be a second example of the so-called `Lorimer burst'. The timing solutions allow us to infer neutron star characteristics such as energy-loss rate, magnetic field strength and evolutionary timescales, as well as facilitating multi-wavelength followup by providing accurate astrometry. All of this enables us to consider the question of whether or not RRATs are in any way special, i.e. a distinct and separate population of neutron stars, as has been previously suggested. We see no reason to consider 'RRAT' as anything other than a detection label, the subject of a selection effect in the parameter space searched. However, single-pulse searches can be utilised to great effect to identify pulsars difficult, or impossible, to find by other means, in particular those with long-periods (half of the PMPS RRATs have periods greater than 4 seconds), high-magnetic field strengths ($B\gtrsim 10^{13}$ G) and pulsars approaching the 'death valley'. The detailed nulling properties of such pulsars are unknown but the mounting evidence suggests a broad range of behaviour in the pulsar population. The group of RRATs fit in to the picture where pulsar magnetospheres switch between stable configurations.