2016MNRAS.458.4456K

We present results of interferometric polarization observations of the recently discovered magnetar J1745-2900 in the vicinity of the Galactic Centre. The observations were made with the Karl G. Jansky Very Large Array (VLA) on 2014 February 21 in the range 40-48 GHz. The full polarization mode and A configuration of the array were used. The average total and linearly polarized flux density of the pulsar amounts to 2.3±0.31 and 1.5±0.2 mJy bea/m, respectively. Analysis shows a rotation measure (RM) of (-67±3) x 10³ rad/m2, which is in good agreement with previous measurements at longer wavelengths. These high-frequency observations are sensitive to RM values of up to ∼2 x 10⁷ rad/m2. However, application of the Faraday RM synthesis technique did not reveal other significant RM components in the pulsar emission. This supports an external nature of a single thin Faraday-rotating screen which should be located close to the Galactic Centre. The Faraday-corrected intrinsic electric vector position angle is 16±9 deg east of north, and coincides with the position angle of the pulsar's transverse velocity. All measurements of the pulsar's RM value to date, including the one presented here, well agree within errors, which points towards a steady nature of the Faraday-rotating medium.