ANTISYMMETRY IN THE FARADAY ROTATION SKY CAUSED BY A NEARBY MAGNETIZED BUBBLE
- Dominion Radio Astrophysical Observatory, HIA-NRC, 717 White Lake Road, P.O. Box 248, Penticton, BC, V2A 6J9 (Canada)
- School of Mathematics and Statistics, Newcastle University, Newcastle upon Tyne, NE1 7RU (United Kingdom)
- ATNF-CSIRO Astronomy and Space Science, P.O. Box 76, Epping NSW 1710 (Australia)
- Physics Department, Private Bag 21, University of Tasmania, Hobart, TAS 7001 (Australia)
- Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia)
- ASTRON, P.O. Box 2, 7990 AA Dwingeloo (Netherlands)
- Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121, Bonn (Germany)
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 {approx}1{sup 0} in the Faraday rotation sky. Our analysis suggests that the observed antisymmetry in the Faraday rotation sky at b>0{sup 0} is dominated by the magnetic field around a local H I 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 20-34 {mu}G 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.
- OSTI ID:
- 21452669
- Journal Information:
- Astrophysical Journal Letters, Vol. 724, Issue 1; Other Information: DOI: 10.1088/2041-8205/724/1/L48; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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