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23rd of February 2018
Pulsar Rotation Measures and Large-scale Magnetic Field Reversals in the Galactic Disk
Han et al. present the measurements of Faraday rotation for 477 pulsars, observed by the Parkes 64 m radio telescope and the Green Bank 100 m radio telescope, to analyze the structure of the large-scale magnetic field in the Galactic disk. The figure above shows the distribution of pulsars and extragalactic radio sources with measured Rotation Measures (RMs) in Galactic coordinates. The central part of the figure shows RMs for pulsars with Galactic latitudes of less than 8 degrees projected on to the Galactic disk and the outer ring shows the distribution of RMs for extragalactic radio sources in the same galactic latitude range. The background in the central part of the figure is an artist's impression of the Galactic structure modified from a NASA/JPL image (Credit: R. Hurt).
Comparison of the compiled rotation measures at different distances reveals large-scale reversals of the field directions between the spiral arms and interarm regions, and the authors develop a model for the disk magnetic field which can reproduce not only these reversals but also the distribution of the observed rotation measures of background sources. This work is published in Han et al. 2018, Astrophysical Journal Supplement Series, vol. 234, article id. 11

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