Hostname: page-component-76fb5796d-2lccl Total loading time: 0 Render date: 2024-04-27T07:07:43.269Z Has data issue: false hasContentIssue false
  • English
  • Français

Remarkable Symmetries in the Milky Way Disc's Magnetic Field

Published online by Cambridge University Press:  02 January 2013

P. P. Kronberg  and
K. J. Newton-McGee
P. P. Kronberg*
Affiliation:
Department of Physics, University of Toronto, Toronto, M5S 1A7, Canada IGPP, Los Alamos National Laboratory, M.S. T006, Los Alamos, NM 87545, USA
K. J. Newton-McGee
Affiliation:
Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006, Australia Australia National Telescope Facility, CSIRO, PO Box 76, Epping, NSW 1710, Australia
*
ECorresponding author. Email: kronberg@physics.utoronto.ca
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We apply a new, expanded compilation of extragalactic source Faraday rotation measures (RM) to investigate the broad underlying magnetic structure of the Galactic disk at latitudes ∣b∣ ≲15° over all longitudes l, where our total number of RMs is comparable to those in the combined Canadian Galactic Plane Survey (CGPS) at ∣b∣ < 4° and the Southern Galactic Plane (SGPS) ∣b∣<1.5°. We report newly revealed, remarkably coherent patterns of RM at ∣b∣≲15° from l∼270° to ∼90° and RM(l) features of unprecedented clarity that replicate in l with opposite sign on opposite sides of the Galactic center. They confirm a highly patterned bisymmetric field structure toward the inner disc, an axisymmetic pattern toward the outer disc, and a very close coupling between the CGPS/SGPS RMs at ∣b∣≲3° (‘mid-plane’) and our new RMs up to ∣b∣∼15° (‘near-plane’). Our analysis also shows the vertical height of the coherent component of the disc field above the Galactic disc's mid-plane—to be ∼1.5 kpc out to ∼6 kpc from the Sun. This identifies the approximate height of a transition layer to the halo field structure. We find no RM sign change across the plane within ∣b∣∼15° in any longitude range. The prevailing disc field pattern and its striking degree of large-scale ordering confirm that our side of the Milky Way has a very organized underlying magnetic structure, for which the inward spiral pitch angle is 5.5°±1° at all ∣b∣ up to ∼12° in the inner semicircle of Galactic longitudes. It decreases to ∼0° toward the anticentre.

Keywords

magnetic fieldsmethods: observationalGalaxy: discGalaxy: structureradio continuum: ISM
Type
Research Article
Information
Publications of the Astronomical Society of Australia , Volume 28 , Issue 2 , 2011 , pp. 171 - 176
Copyright
Copyright © Astronomical Society of Australia 2011

References

Auger Collaboration, 2007, Science, 318, 938CrossRefGoogle Scholar
Beck, R., Brandenburg, A., Moss, D., Shukurov, A. & Sokoloff, D. D., 1997, ARAA, 34, 155CrossRefGoogle Scholar
Beuermann, K., Kanbach, G. & Berkhuijsen, E. M., 1985, A&A, 153, 17Google Scholar
Brown, J. C., Haverkorn, M., Gaensler, B. M., Taylor, A. R., Bizunok, N. S., McClure-Griffiths, N. M., Dickey, J. M. & Green, A. J., 2007, ApJ, 663, 238CrossRefGoogle Scholar
Brown, J. C., Taylor, A. R. & Jackel, B. J., 2003, ApJS, 145, 213CrossRefGoogle Scholar
Frick, P., Stepanov, R., Shukurov, A. & Sokoloff, D., 2001, MNRAS, 325, 649CrossRefGoogle Scholar
Gaensler, B. M., Madsen, G. J., Chatterjee, S. & Mao, S. A., 2008, PASA, 25, 184CrossRefGoogle Scholar
Haverkorn, M., Gaensler, B. M., Brown, J. C., Bizunok, N. S., McClure-Griffiths, N. M., Dickey, J. M. & Green, A. J., 2006, ApJL, 637, L33CrossRefGoogle Scholar
Han, J. L., Manchester, R. N. & Qiao, G. J., 1999, MNRAS, 306, 371CrossRefGoogle Scholar
Han, J. L., Manchester, R. N. & Qiao, G. J., 2006, ApJ, 642, 868CrossRefGoogle Scholar
Heiles, C., 1996, ApJ, 462, 43Google Scholar
Jansson, R., Farrar, G. R., Waelkens, A. H. & Enßlin, T. E., 2009, J. Cosm. & Particle Physics, 7, 21Google Scholar
Klein, U., Mack, K.-H., Gregorini, L. & Vigotti, M., 2003, A&A, 406, 579Google Scholar
Manchester, R. N., 1972, ApJ, 172, 43CrossRefGoogle Scholar
Manchester, R. N., 1974, ApJ, 188, 637CrossRefGoogle Scholar
Mao, S. A., Gaensler, B. M., Stanimirovic, S., Haverkorn, M., McClure-Griffiths, N. M., Staveley-Smith, L. & Dickey, J. M., 2008, ApJ, 688, 1029CrossRefGoogle Scholar
Men, H., Ferriére, K. & Han, J. L., 2008, A&A, 486, 819Google Scholar
Pshirkov, M. S., Tinyakov, P. G., Kronberg, P. P. & Newton-McGee, K. J., 2011, ApJ (submitted)Google Scholar
Shukurov, A., Sokoloff, D., Subramanian, K. & Brandenburg, A., 2006, A&A, 448, L33Google Scholar
Sun, X. H., Reich, W., Waelkens, A. & Enßlin, T. A., 2008, A&A, 477, 573Google Scholar
Simard-Normandin, M. & Kronberg, P. P., 1979, Nature, 279, 115CrossRefGoogle Scholar
Simard-Normandin, M. & Kronberg, P. P., 1980, ApJ, 242, 74CrossRefGoogle Scholar
Simard-Normandin, M., Kronberg, P. P. & Button, S., 1981, ApJS, 45, 97CrossRefGoogle Scholar
Taylor, A. R., Stil, J. M. & Sunstrum, C., 2009, ApJ, 702, 1230CrossRefGoogle Scholar
Vallée, J. P., 2008, ApJ, 681, 303CrossRefGoogle Scholar
Vallée, J. P., 1992, A&A, 255, 100Google Scholar
Van Eck, C. L., Brown, J. C., Stil, J. M., Rae, K., Gaensler, B. M., Shukurov, A., Taylor, A. R., Haverkorn, M., Kronberg, P. P. & McClure-Griffiths, N. M., 2011, ApJ, 728, 97CrossRefGoogle Scholar
Weisberg, J. M., Cordes, J. M., Kuan, B., Devine, K. E., Green, J. T. & Backer, D. C., 2004, ApJS, 150, 317CrossRefGoogle Scholar