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Title: THE RADIO CONTINUUM STRUCTURE OF CENTAURUS A AT 1.4 GHz

Abstract

A 45 deg{sup 2} radio continuum imaging campaign of the nearest radio galaxy, Centaurus A, is reported. Using the Australia Telescope Compact Array and the Parkes 64 m radio telescope at 1.4 GHz, the spatial resolution of the resultant image is {approx}600 pc ({approx}50''), resolving the {approx}>500 kpc giant radio lobes with approximately five times better physical resolution compared to any previous image, and making this the most detailed radio continuum image of any radio galaxy to date. In this paper, we present these new data and discuss briefly some of the most interesting morphological features that we have discovered in the images. The two giant outer lobes are highly structured and considerably distinct. The southern part of the giant northern lobe naturally extends out from the northern middle lobe with uniformly north-streaming emission. The well known northern loop is resolved into a series of semi-regular shells with a spacing of approximately 25 kpc. The northern part of the giant northern lobe also contains identifiable filaments and partial ring structures. As seen in previous single-dish images at lower angular resolution, the giant southern lobe is not physically connected to the core at radio wavelengths. Almost the entirety of the giantmore » southern lobe is resolved into a largely chaotic and mottled structure which appears considerably different (morphologically) to the diffuse regularity of the northern lobe. We report the discovery of a vertex and a vortex near the western boundary of the southern lobe, two striking, high surface brightness features that are named based on their morphology and not their dynamics (which are presently unknown). The vortex and vertex are modeled as reaccelerated lobe emission due to shocks from the active galactic nucleus itself or from the passage of a dwarf elliptical galaxy through the lobe. Preliminary polarimetric and spectral index studies support a plasma reacceleration model and could explain the origin of the Faraday rotation structure detected in the southern lobe. In addition, there are a series of low surface brightness wisps detected around the edges of both the giant lobes.« less

Authors:
; ; ; ; ; ;  [1];  [2];  [3]; ; ; ;  [4];  [5];  [6]
  1. CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia)
  2. School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington (New Zealand)
  3. National Radio Astronomical Observatory, Charlottesville, P.O. Box O, 1003 Lopezville Road, Socorro, NM 87801-0387 (United States)
  4. Sydney Institute for Astronomy, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia)
  5. Astronomisches Institut der Universitaet Bochum, Universitaetsstr. 150, D-44801 Bochum (Germany)
  6. Department of Astrophysics/IMAPP, Radboud University Nijmegen, P.O. Box 9010, NL-6500 GL Nijmegen (Netherlands)
Publication Date:
OSTI Identifier:
21587433
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 740; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/740/1/17; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BRIGHTNESS; FARADAY EFFECT; IMAGE PROCESSING; MORPHOLOGY; RADIO GALAXIES; COSMIC RADIO SOURCES; GALAXIES; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; PROCESSING

Citation Formats

Feain, I J, Cornwell, T J, Ekers, R D, Calabretta, M R, Norris, R P, O'Sullivan, S, McClure-Griffiths, N M, Johnston-Hollitt, M, Ott, J, Lindley, E, Gaensler, B M, Murphy, T, Bland-Hawthorn, J, Middelberg, E, and Jiraskova, S. THE RADIO CONTINUUM STRUCTURE OF CENTAURUS A AT 1.4 GHz. United States: N. p., 2011. Web. doi:10.1088/0004-637X/740/1/17; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Feain, I J, Cornwell, T J, Ekers, R D, Calabretta, M R, Norris, R P, O'Sullivan, S, McClure-Griffiths, N M, Johnston-Hollitt, M, Ott, J, Lindley, E, Gaensler, B M, Murphy, T, Bland-Hawthorn, J, Middelberg, E, & Jiraskova, S. THE RADIO CONTINUUM STRUCTURE OF CENTAURUS A AT 1.4 GHz. United States. https://doi.org/10.1088/0004-637X/740/1/17; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
Feain, I J, Cornwell, T J, Ekers, R D, Calabretta, M R, Norris, R P, O'Sullivan, S, McClure-Griffiths, N M, Johnston-Hollitt, M, Ott, J, Lindley, E, Gaensler, B M, Murphy, T, Bland-Hawthorn, J, Middelberg, E, and Jiraskova, S. 2011. "THE RADIO CONTINUUM STRUCTURE OF CENTAURUS A AT 1.4 GHz". United States. https://doi.org/10.1088/0004-637X/740/1/17; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
@article{osti_21587433,
title = {THE RADIO CONTINUUM STRUCTURE OF CENTAURUS A AT 1.4 GHz},
author = {Feain, I J and Cornwell, T J and Ekers, R D and Calabretta, M R and Norris, R P and O'Sullivan, S and McClure-Griffiths, N M and Johnston-Hollitt, M and Ott, J and Lindley, E and Gaensler, B M and Murphy, T and Bland-Hawthorn, J and Middelberg, E and Jiraskova, S},
abstractNote = {A 45 deg{sup 2} radio continuum imaging campaign of the nearest radio galaxy, Centaurus A, is reported. Using the Australia Telescope Compact Array and the Parkes 64 m radio telescope at 1.4 GHz, the spatial resolution of the resultant image is {approx}600 pc ({approx}50''), resolving the {approx}>500 kpc giant radio lobes with approximately five times better physical resolution compared to any previous image, and making this the most detailed radio continuum image of any radio galaxy to date. In this paper, we present these new data and discuss briefly some of the most interesting morphological features that we have discovered in the images. The two giant outer lobes are highly structured and considerably distinct. The southern part of the giant northern lobe naturally extends out from the northern middle lobe with uniformly north-streaming emission. The well known northern loop is resolved into a series of semi-regular shells with a spacing of approximately 25 kpc. The northern part of the giant northern lobe also contains identifiable filaments and partial ring structures. As seen in previous single-dish images at lower angular resolution, the giant southern lobe is not physically connected to the core at radio wavelengths. Almost the entirety of the giant southern lobe is resolved into a largely chaotic and mottled structure which appears considerably different (morphologically) to the diffuse regularity of the northern lobe. We report the discovery of a vertex and a vortex near the western boundary of the southern lobe, two striking, high surface brightness features that are named based on their morphology and not their dynamics (which are presently unknown). The vortex and vertex are modeled as reaccelerated lobe emission due to shocks from the active galactic nucleus itself or from the passage of a dwarf elliptical galaxy through the lobe. Preliminary polarimetric and spectral index studies support a plasma reacceleration model and could explain the origin of the Faraday rotation structure detected in the southern lobe. In addition, there are a series of low surface brightness wisps detected around the edges of both the giant lobes.},
doi = {10.1088/0004-637X/740/1/17; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)},
url = {https://www.osti.gov/biblio/21587433}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 740,
place = {United States},
year = {Mon Oct 10 00:00:00 EDT 2011},
month = {Mon Oct 10 00:00:00 EDT 2011}
}