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dc.contributor.authorFeain, I.
dc.contributor.authorEkers, R.
dc.contributor.authorMurphy, T.
dc.contributor.authorGaensler, B.
dc.contributor.authorMacquart, Jean-pierre
dc.contributor.authorNorris, R.
dc.contributor.authorCornwell, T.
dc.contributor.authorJohnston-Hollitt, M.
dc.contributor.authorOtt, J.
dc.contributor.authorMiddelburg, E.
dc.date.accessioned2017-01-30T11:32:43Z
dc.date.available2017-01-30T11:32:43Z
dc.date.created2010-03-22T20:02:15Z
dc.date.issued2009
dc.identifier.citationFeain, I and Ekers, R and Murphy, T and Gaensler, B and Macquart, Jean-Pierre and Norris, R and Cornwell, T and Johnston-Hollitt, M and Ott, J and Middelburg, E. 2009. Faraday Rotation Structure on Kiloparsec Scales in the Radio Lobes of Centaurus A. The Astrophysical Journal. 707 (1): pp. 114-125.
dc.identifier.urihttp://hdl.handle.net/20.500.11937/12762
dc.identifier.doi10.1088/0004-637X/707/1/114
dc.description.abstract

We present the results of an Australia Telescope Compact Array 1.4 GHz spectropolarimetric aperture synthesis survey of 34 deg2 centered on Centaurus A-NGC 5128. A catalog of 1005 extragalactic compact radio sources in the field to a continuum flux density of 3 mJy beam-1 is provided along with a table of Faraday rotation measures (RMs) and linear polarized intensities for the 28% of sources with high signal to noise in linear polarization. We use the ensemble of 281 background polarized sources as line-of-sight probes of the structure of the giant radio lobes of Centaurus A. This is the first time such a method has been applied to radio galaxy lobes and we explain how it differs from the conventional methods that are often complicated by depth and beam depolarization effects. Assuming a magnetic field strength in the lobes of 1.3B1 G, where B1 = 1 is implied by equipartition between magnetic fields and relativistic particles, the upper limit we derive on the maximum possible difference between the average RM of 121 sources behind Centaurus A and the average RM of the 160 sources along sightlines outside Centaurus A implies an upper limit on the volume-averaged thermal plasma density in the giant radio lobes of (ne) <5 x 10-5B-11 cm-3. We use an RM structure function analysis and report the detection of a turbulent RM signal, with rms sRM = 17 rad m-2 and scale size 0.3, associated with the southern giant lobe. We cannot verify whether this signal arises from turbulent structure throughout the lobe or only in a thin skin (or sheath) around the edge, although we favor the latter. The RM signal is modeled as possibly arising from a thin skin with a thermal plasma density equivalent to the Centaurus intragroup medium density and a coherent magnetic field that reverses its sign on a spatial scale of 20 kpc. For a thermal density of n1 10-3 cm-3, the skin magnetic field strength is 0.8 n-1 1 G.

dc.publisherThe American Astronomical Society
dc.subjectgalaxies
dc.subjectindividual (Centaurus A
dc.subjectNGC 5128) techniques
dc.subjectpolarimetric
dc.subjectinterferometric techniques
dc.titleFaraday Rotation Structure on Kiloparsec Scales in the Radio Lobes of Centaurus A
dc.typeJournal Article
dcterms.source.volume707
dcterms.source.number1
dcterms.source.startPage114
dcterms.source.endPage125
dcterms.source.issn0004637X
dcterms.source.titleThe Astrophysical Journal
curtin.note

Copyright © 2009 The American Astronomical Society ("AAS")-[The Astrophysical Journal (ApJ) Feain, I., 2009 ApJS 707 (1), 114-125.]

curtin.accessStatusOpen access via publisher
curtin.facultyFaculty of Science and Engineering
curtin.facultyCurtin Institute of Radio Astronomy


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