CHANG-ES XV. Large-scale magnetic field reversals in the radio halo of NGC 4631
AuthorMora-Partiarroyo, Silvia Carolina
Vargas, Carlos J.
Walterbos, René A. M.
Rand, Richard J.
AffiliationUniv Arizona, Dept Astron
Univ Arizona, Steward Observ
Keywordsgalaxies: individual: NGC4631
galaxies: magnetic fields
radio continuum: galaxies
MetadataShow full item record
PublisherEDP SCIENCES S A
CitationMora-Partiarroyo, S. C., Krause, M., Basu, A., Beck, R., Wiegert, T., Irwin, J., … English, J. (2019). CHANG-ES. Astronomy & Astrophysics, 632, A11. https://doi.org/10.1051/0004-6361/201935961
JournalASTRONOMY & ASTROPHYSICS
RightsCopyright © S. C. Mora-Partiarroyo et al. 2019. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Open Access funding provided by Max Planck Society.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractAims. NGC4631 is an interacting galaxy which exhibits one of the largest gaseous halos observed among edge-on galaxies. We aim to examine the synchrotron and polarization properties of its disk and halo emission with new radio continuum data. Methods. Radio continuum observations of NGC4631 were performed with the Karl G. Jansky Very Large Array at C-band (5.99 GHz) in the C and D array configurations, and at L-band (1.57 GHz) in the B, C, and D array configurations. The Rotation Measure Synthesis algorithm was utilized to derive the polarization properties. Results. We detected linearly polarized emission at C-band and L-band. The magnetic field in the halo is characterized by strong vertical components above and below the central region of the galaxy. The magnetic field in the disk is only clearly seen in the eastern side of NGC4631, where it is parallel to the plane of the major axis of the galaxy. We detected for the first time a large-scale, smooth Faraday depth pattern in a halo of an external spiral galaxy, which implies the existence of a regular (coherent) magnetic field. A quasi-periodic pattern in Faraday depth with field reversals was found in the northern halo of the galaxy. Conclusions. The field reversals in the northern halo of NGC4631, together with the observed polarization angles, indicate giant magnetic ropes with alternating directions. To our knowledge, this is the first time such reversals are observed in an external galaxy.
VersionFinal published version
SponsorsGerman Federal Ministry of Education and Research (BMBF)Federal Ministry of Education & Research (BMBF) [05A17PB1]; NSFNational Science Foundation (NSF) [AST-1615594]
Except where otherwise noted, this item's license is described as Copyright © S. C. Mora-Partiarroyo et al. 2019. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Open Access funding provided by Max Planck Society.
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