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Antisymmetry in the faraday rotation sky caused by a nearby magnetized bubble


Wolleben, M and Fletcher, A and Landecker, L and Carretti, E and Dickey, JM and Gaensler, BM and Haverkorn, M and McClure-Griffiths, N and Reich, W and Taylor, AR, Antisymmetry in the faraday rotation sky caused by a nearby magnetized bubble, Astrophysical Journal, 724, (1) pp. L48-L52. ISSN 0004-637X (2010) [Refereed Article]

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Copyright 2010 The American Astronomical Society

DOI: doi:10.1088/2041-8205/724/1/L48


Rotation measures (RMs) of pulsars and extragalactic point sources have been known to reveal large-scale antisymmetries in the Faraday rotation sky with respect to the Galactic plane and halo that have been interpreted as signatures of the mean magnetic field in the Galactic halo. We describe Faraday rotation measurements of the diffuse Galactic polarized radio emission over a large region in the northern Galactic hemisphere. Through application of RM synthesis we achieve sensitive Faraday rotation maps with high angular resolution, capable of revealing fine-scale structures of ∼1◦ in the Faraday rotation sky. Our analysis suggests that the observed antisymmetry in the Faraday rotation sky at b > 0◦ is dominated by the magnetic field around a local Hi bubble at a distance of 100 pc, and not by the magnetic field of the Galactic halo. We derive physical properties of the magnetic field of this shell, which we find to be 20–34μG strong. It is clear that the diffuse polarized radio emission contains important information about the local magneto-ionic medium, which cannot yet be derived from Faraday RMs of extragalactic sources or pulsars alone.

Item Details

Item Type:Refereed Article
Keywords:Galaxy: halo – ISM: bubbles – ISM: magnetic fields – magnetic fields – polarization
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Dickey, JM (Professor John Dickey)
ID Code:65313
Year Published:2010
Web of Science® Times Cited:29
Deposited By:Physics
Deposited On:2010-10-29
Last Modified:2013-01-17

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