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A new class of extragalactic radio sources with one-sided structure?

Nature volume 339, pages 286–288 (1989)Cite this article

Abstract

EXTRAGALACTIC radio sources with extended emission on only one side of the active galaxy usually have very dominant radio cores1–5, large misalignments between the structure inferred from Very Long Baseline Interferometry and that on the arcsecond scale1,6,7, and often evidence of 'blazar' characteristics and superluminal motion in the nucleus8. These properties are usually attributed to relativistic motion of nuclear jets in sources inclined at small angles to the line of sight. From a large survey of possible one-sided sources made with both MERLIN and the Very Large Array, we have been able to identify a class of one-sided sources that are dominated by their extended emission while the lower limits on their degree of asymmetry, inferred from our MERLIN observations, are amongst the highest known. These weak-cored one-sided sources appear to be inconsistent with the 'unified scheme9–15, which attempts to explain core-dominated sources as being the relativistically beamed counterparts of the lobe-dominated ones. We discuss possible explanations for this class of sources and suggest tests to distinguish between the different alternatives.

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Authors and Affiliations

  1. Nuffield Radio Astronomy Laboratories, Jodrell Bank, University of Manchester, Macclesfield, Cheshire, SK119DL, UK

    D. J. Saikia, T. W. B. Muxlow & A. K. Tzioumis

  2. Tata Institute of Fundamental Research, Post Box 1234, Bangalore, 560 012, India

    D. J. Saikia

  3. Istituto di Radioastronomia, Via Irnerio 46, 1-40126, Bologna, Italy

    W. Junor

  4. National Radio Astronomy Observatory, PO Box O, Socorro, New Mexico, 87801, USA

    W. Junor

Authors
  1. D. J. Saikia
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  2. W. Junor
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  3. T. W. B. Muxlow
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  4. A. K. Tzioumis
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Saikia, D., Junor, W., Muxlow, T. et al. A new class of extragalactic radio sources with one-sided structure?. Nature 339, 286–288 (1989). https://doi.org/10.1038/339286a0

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