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FARADAY TOMOGRAPHY OF THE NORTH POLAR SPUR: CONSTRAINTS ON THE DISTANCE TO THE SPUR AND ON THE MAGNETIC FIELD OF THE GALAXY

Sun, X. H.; Landecker, T. L.; Gaensler, B M; Carretti, E.; Reich, W; Leahy, J. P.; McClure-Griffiths, Naomi; Crocker, Roland; Wolleben, M.; Haverkorn, Marijke; Douglas, K.A.; Gray, A.D.

Description

We present radio continuum and polarization images of the North Polar Spur (NPS) from the Global Magneto-ionic Medium Survey conducted with the Dominion Radio Astrophysical Observatory 26 m Telescope. We fit polarization angle versus wavelength squared over 2048 frequency channels from 1280 to 1750 MHz to obtain a Faraday rotation measure (RM) map of the NPS. Combining this RM map with a published Faraday depth (FD) map of the entire Galaxy in this direction, we derive the FD introduced by the...[Show more]

dc.contributor.authorSun, X. H.
dc.contributor.authorLandecker, T. L.
dc.contributor.authorGaensler, B M
dc.contributor.authorCarretti, E.
dc.contributor.authorReich, W
dc.contributor.authorLeahy, J. P.
dc.contributor.authorMcClure-Griffiths, Naomi
dc.contributor.authorCrocker, Roland
dc.contributor.authorWolleben, M.
dc.contributor.authorHaverkorn, Marijke
dc.contributor.authorDouglas, K.A.
dc.contributor.authorGray, A.D.
dc.date.accessioned2018-11-29T22:52:32Z
dc.date.available2018-11-29T22:52:32Z
dc.identifier.issn0004-637X
dc.identifier.urihttp://hdl.handle.net/1885/152203
dc.description.abstractWe present radio continuum and polarization images of the North Polar Spur (NPS) from the Global Magneto-ionic Medium Survey conducted with the Dominion Radio Astrophysical Observatory 26 m Telescope. We fit polarization angle versus wavelength squared over 2048 frequency channels from 1280 to 1750 MHz to obtain a Faraday rotation measure (RM) map of the NPS. Combining this RM map with a published Faraday depth (FD) map of the entire Galaxy in this direction, we derive the FD introduced by the NPS and the Galactic interstellar medium (ISM) in front of and behind the NPS. The FD contributed by the NPS is close to zero, indicating that the NPS is an emitting only feature. The FD caused by the ISM in front of the NPS is consistent with zero at b > 50°, implying that this part of the NPS is local at a distance of approximately several hundred parsecs. The FD contributed by the ISM behind the NPS gradually increases with Galactic latitude up to b = 44°, and decreases at higher Galactic latitudes. This implies that either the part of the NPS at b < 44° is distant or the NPS is local but there is a sign change of the large-scale magnetic field. If the NPS is local, there is then no evidence for a large-scale anti-symmetry pattern in the FD of the Milky Way. The FD introduced by the ISM behind the NPS at latitudes b > 50° can be explained by including a coherent vertical magnetic field.
dc.format.mimetypeapplication/pdf
dc.publisherIOP Publishing
dc.sourceThe Astrophysical Journal
dc.titleFARADAY TOMOGRAPHY OF THE NORTH POLAR SPUR: CONSTRAINTS ON THE DISTANCE TO THE SPUR AND ON THE MAGNETIC FIELD OF THE GALAXY
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume811
dc.date.issued2015
local.identifier.absfor020103 - Cosmology and Extragalactic Astronomy
local.identifier.absfor020104 - Galactic Astronomy
local.identifier.absfor020106 - High Energy Astrophysics; Cosmic Rays
local.identifier.ariespublicationU3488905xPUB14154
local.type.statusPublished Version
local.contributor.affiliationSun, X. H., University of Sydney
local.contributor.affiliationLandecker, T. L., National Research Council Canada
local.contributor.affiliationGaensler, B M, University of Sydney
local.contributor.affiliationCarretti, E., CSIRO Astronomy and Space Science
local.contributor.affiliationReich, W, Max-Planck-Institut für Radioastronomie
local.contributor.affiliationLeahy, J. P., University of Manchester
local.contributor.affiliationMcClure-Griffiths, Naomi, College of Science, ANU
local.contributor.affiliationCrocker, Roland, College of Science, ANU
local.contributor.affiliationWolleben, M., Herzberg University of Astrophyics
local.contributor.affiliationHaverkorn, Marijke, Leiden University
local.contributor.affiliationDouglas, K.A., National Research Council Canada
local.contributor.affiliationGray, A.D., National Research Council Canada
local.bibliographicCitation.issue1
local.identifier.doi10.1088/0004-637X/811/1/40
local.identifier.absseo970102 - Expanding Knowledge in the Physical Sciences
dc.date.updated2018-11-29T07:46:49Z
local.identifier.scopusID2-s2.0-84945543579
local.identifier.thomsonID000363471600041
dcterms.accessRightsOpen Access
CollectionsANU Research Publications

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