Galaxies (Nov 2018)

The Extraordinary Linear Polarisation Structure of the Southern Centaurus A Lobe Revealed by ASKAP

  • Craig S. Anderson,
  • George Heald,
  • Shane P. O’Sullivan,
  • John D. Bunton,
  • Ettore Carretti,
  • Aaron P. Chippendale,
  • Jordan D. Collier,
  • Jamie S. Farnes,
  • Bryan M. Gaensler,
  • Lisa Harvey-Smith,
  • Bärbel S. Koribalski,
  • Tom L. Landecker,
  • Emil Lenc,
  • Naomi M. McClure-Griffiths,
  • Daniel Mitchell,
  • Lawrence Rudnick,
  • Jennifer West

DOI
https://doi.org/10.3390/galaxies6040127
Journal volume & issue
Vol. 6, no. 4
p. 127

Abstract

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We present observations of linear polarisation in the southern radio lobe of Centaurus A, conducted during commissioning of the Australian Square Kilometre Array Pathfinder (ASKAP) telescope. We used 16 antennas to observe a 30 square degree region in a single 12-h pointing over a 240 MHz band centred on 913 MHz. Our observations achieve an angular resolution of 26 × 33 arcseconds (480 parsecs), a maximum recoverable angular scale of 30 arcminutes, and a full-band sensitivity of 85 μ Jy beam − 1 . The resulting maps of polarisation and Faraday rotation are amongst the most detailed ever made for radio lobes, with order 10 5 resolution elements covering the source. We describe several as-yet unreported observational features of the lobe, including its detailed peak Faraday depth structure, and intricate networks of depolarised filaments. These results demonstrate the exciting capabilities of ASKAP for widefield radio polarimetry.

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