Untangling the magnetic fields in spiral galaxy NGC 6946 with wide-band polarimetry

Anna Williams, George Heald, Eric M. Wilcots, Ellen Gould Zweibel

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We present 13 cm polarization observations of nearby spiral galaxy NGC 6946. These data provide a new perspective into the magnetic field structure of this galaxy. Previous observations show strong depolarization between 6 cm and 22 cm, and we show that the morphology of the 13 cm polarization bridges this gap. We combine all available high resolution polarization observations to fit models of the line of sight magnetic field structure across the disk. We find simple screens of Faraday rotation, differential Faraday rotation, and internal Faraday dispersion are insufficient to explain the observed depolarization, and present the results of the best fit models. We discuss how future broadband observations and improved models will help reconstruct the full 3D model of the magnetic field structure in the disks and haloes of galaxies.
Original languageEnglish
JournalAmerican Astronomical Society Meeting
Publication statusPublished - Jan-2017

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