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Title: MAGNETIC FIELD STRUCTURE OF THE LARGE MAGELLANIC CLOUD FROM FARADAY ROTATION MEASURES OF DIFFUSE POLARIZED EMISSION

Abstract

We present a study of the magnetic field of the Large Magellanic Cloud (LMC), carried out using diffuse polarized synchrotron emission data at 1.4 GHz acquired at the Parkes Radio Telescope and the Australia Telescope Compact Array. The observed diffuse polarized emission is likely to originate above the LMC disk on the near side of the galaxy. Consistent negative rotation measures (RMs) derived from the diffuse emission indicate that the line-of-sight magnetic field in the LMC's near-side halo is directed coherently away from us. In combination with RMs of extragalactic sources that lie behind the galaxy, we show that the LMC's large-scale magnetic field is likely to be of quadrupolar geometry, consistent with the prediction of dynamo theory. On smaller scales, we identify two brightly polarized filaments southeast of the LMC, associated with neutral hydrogen arms. The filaments' magnetic field potentially aligns with the direction toward the Small Magellanic Cloud (SMC). We suggest that tidal interactions between the SMC and the LMC in the past 10{sup 9} years are likely to have shaped the magnetic field in these filaments.

Authors:
 [1]; ;  [2];  [3];  [4];  [5];  [6];  [7];  [8];  [9]
  1. National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States)
  2. Australia Telescope National Facility, CSIRO Astronomy and Space Science, Epping, NSW 1710 (Australia)
  3. Sydney Institute for Astronomy, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia)
  4. Department of Astrophysics, Radboud University, P.O. Box 9010, 6500-GL Nijmegen (Netherlands)
  5. Max-Planck-Institut fuer Radioastronomie, D-53121 Bonn (Germany)
  6. Square Kilometre Array South Africa, The Park, Pinelands 7405 (South Africa)
  7. Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States)
  8. Physics Department, University of Tasmania, Hobart, TAS 7001 (Australia)
  9. International Centre for Radio Astronomy Research (ICRAR), The University of Western Australia, Crawley, WA 6009 (Australia)
Publication Date:
OSTI Identifier:
22086469
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 759; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; FARADAY EFFECT; GHZ RANGE; HYDROGEN; MAGELLANIC CLOUDS; MAGNETIC FIELDS; PHOTON EMISSION; POLARIZATION; RADIO TELESCOPES; RADIOASTRONOMY; ROTATION; SYNCHROTRON RADIATION

Citation Formats

Mao, S. A., McClure-Griffiths, N. M., McConnell, D., Gaensler, B. M., Haverkorn, M., Beck, R., Wolleben, M., Stanimirovic, S., Dickey, J. M., and Staveley-Smith, L., E-mail: mao@astro.wisc.edu. MAGNETIC FIELD STRUCTURE OF THE LARGE MAGELLANIC CLOUD FROM FARADAY ROTATION MEASURES OF DIFFUSE POLARIZED EMISSION. United States: N. p., 2012. Web. doi:10.1088/0004-637X/759/1/25.
Mao, S. A., McClure-Griffiths, N. M., McConnell, D., Gaensler, B. M., Haverkorn, M., Beck, R., Wolleben, M., Stanimirovic, S., Dickey, J. M., & Staveley-Smith, L., E-mail: mao@astro.wisc.edu. MAGNETIC FIELD STRUCTURE OF THE LARGE MAGELLANIC CLOUD FROM FARADAY ROTATION MEASURES OF DIFFUSE POLARIZED EMISSION. United States. doi:10.1088/0004-637X/759/1/25.
Mao, S. A., McClure-Griffiths, N. M., McConnell, D., Gaensler, B. M., Haverkorn, M., Beck, R., Wolleben, M., Stanimirovic, S., Dickey, J. M., and Staveley-Smith, L., E-mail: mao@astro.wisc.edu. Thu . "MAGNETIC FIELD STRUCTURE OF THE LARGE MAGELLANIC CLOUD FROM FARADAY ROTATION MEASURES OF DIFFUSE POLARIZED EMISSION". United States. doi:10.1088/0004-637X/759/1/25.
@article{osti_22086469,
title = {MAGNETIC FIELD STRUCTURE OF THE LARGE MAGELLANIC CLOUD FROM FARADAY ROTATION MEASURES OF DIFFUSE POLARIZED EMISSION},
author = {Mao, S. A. and McClure-Griffiths, N. M. and McConnell, D. and Gaensler, B. M. and Haverkorn, M. and Beck, R. and Wolleben, M. and Stanimirovic, S. and Dickey, J. M. and Staveley-Smith, L., E-mail: mao@astro.wisc.edu},
abstractNote = {We present a study of the magnetic field of the Large Magellanic Cloud (LMC), carried out using diffuse polarized synchrotron emission data at 1.4 GHz acquired at the Parkes Radio Telescope and the Australia Telescope Compact Array. The observed diffuse polarized emission is likely to originate above the LMC disk on the near side of the galaxy. Consistent negative rotation measures (RMs) derived from the diffuse emission indicate that the line-of-sight magnetic field in the LMC's near-side halo is directed coherently away from us. In combination with RMs of extragalactic sources that lie behind the galaxy, we show that the LMC's large-scale magnetic field is likely to be of quadrupolar geometry, consistent with the prediction of dynamo theory. On smaller scales, we identify two brightly polarized filaments southeast of the LMC, associated with neutral hydrogen arms. The filaments' magnetic field potentially aligns with the direction toward the Small Magellanic Cloud (SMC). We suggest that tidal interactions between the SMC and the LMC in the past 10{sup 9} years are likely to have shaped the magnetic field in these filaments.},
doi = {10.1088/0004-637X/759/1/25},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 759,
place = {United States},
year = {2012},
month = {11}
}