Discovery and Follow-up of Rotating Radio Transients with the Green Bank and LOFAR Telescopes

TL;DR

This paper reports the discovery of 21 new Rotating Radio Transients (RRATs) using the Green Bank Telescope and LOFAR, introduces a new detection algorithm, and analyzes their properties and relationship to pulsars.

Contribution

The paper presents a new candidate sifting algorithm, RRATtrap, for detecting RRATs and Fast Radio Bursts, and provides detailed follow-up observations and statistical analysis of newly discovered RRATs.

Findings

21 new RRATs discovered with DM 15-97 pc cm$^{-3}$

RRATs have periods from 240 ms to 3.4 s and burst rates of 20-400 pulses/hr

RRATs' spatial and DM distributions match those of pulsars in the same survey

Abstract

We have discovered 21 Rotating Radio Transients (RRATs) in data from the Green Bank Telescope (GBT) 350-MHz Drift-scan and the Green Bank North Celestial Cap pulsar surveys using a new candidate sifting algorithm. RRATs are pulsars with sporadic emission that are detected through their bright single pulses rather than Fourier domain searches. We have developed {\tt RRATtrap}, a single-pulse sifting algorithm that can be integrated into pulsar survey data analysis pipelines in order to find RRATs and Fast Radio Bursts. We have conducted follow-up observations of our newly discovered sources at several radio frequencies using the GBT and Low Frequency Array (LOFAR), yielding improved positions and measurements of their periods, dispersion measures, and burst rates, as well as phase-coherent timing solutions for four of them. The new RRATs have dispersion measures (DMs) ranging from 15 to 97 pc cm$^{-3}$, periods of 240 ms to 3.4 s, and estimated burst rates of 20 to 400 pulses hr$^{-1}$ at 350 MHz. We use this new sample of RRATs to perform statistical comparisons between RRATs and canonical pulsars in order to shed light on the relationship between the two populations. We find that the DM and spatial distributions of the RRATs agree with those of the pulsars found in the same survey. We find evidence that slower pulsars (i.e. $P>200$ ms) are preferentially more likely to emit bright single pulses than are faster pulsars ($P<200$ ms), although this conclusion is tentative. Our results are consistent with the proposed link between RRATs, transient pulsars, and canonical pulsars as sources in various parts of the pulse activity spectrum.