University of Hertfordshire

From the same journal

From the same journal

A search for long-timescale, low-frequency radio transients

Research output: Contribution to journalArticlepeer-review


  • 1611.08354

    Accepted author manuscript, 3.08 MB, PDF document


  • Tara Murphy
  • David L. Kaplan
  • Steve Croft
  • Christene Lynch
  • J. R. Callingham
  • Keith Bannister
  • Martin E. Bell
  • Natasha Hurley-Walker
  • Paul Hancock
  • Jack Line
  • Antonia Rowlinson
  • Emil Lenc
  • H. T. Intema
  • P. Jagannathan
  • Ronald D. Ekers
  • Steven Tingay
  • Fang Yuan
  • Christian Wolf
  • Christopher A. Onken
  • K. S. Dwarakanath
  • And 13 others
  • B. -Q. For
  • B. M. Gaensler
  • L. Hindson
  • M. Johnston-Hollitt
  • A. D. Kapinska
  • B. McKinley
  • J. Morgan
  • A. R. Offringa
  • P. Procopio
  • L. Staveley-Smith
  • R. Wayth
  • C. Wu
  • Q. Zheng
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Original languageEnglish
Pages (from-to)1944–1953
JournalMonthly Notices of the Royal Astronomical Society
Early online date30 Nov 2016
Publication statusPublished - 11 Apr 2017


We present a search for transient and highly variable sources at low radio frequencies (150-200 MHz) that explores long timescales of 1-3 years. We conducted this search by comparing the TIFR GMRT Sky Survey Alternative Data Release 1 (TGSS ADR1) and the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey catalogues. To account for the different completeness thresholds in the individual surveys, we searched for compact GLEAM sources above a flux density limit of 100 mJy that were not present in the TGSS ADR1; and also for compact TGSS ADR1 sources above a flux density limit of 200 mJy that had no counterpart in GLEAM. From a total sample of 234 333 GLEAM sources and 275 612 TGSS ADR1 sources in the overlap region between the two surveys, there were 99658 GLEAM sources and 38 978 TGSS ADR sources that passed our flux density cutoff and compactness criteria. Analysis of these sources resulted in three candidate transient sources. Further analysis ruled out two candidates as imaging artefacts. We analyse the third candidate and show it is likely to be real, with a flux density of 182 +/- 26 mJy at 147.5 MHz. This gives a transient surface density of rho = (6.2 +/- 6) x 10-5 deg-2 . We present initial follow-up observations and discuss possible causes for this candidate. The small number of spurious sources from this search demonstrates the high reliability of these two new low-frequency radio catalogues.


This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2017 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.


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