Rotation Measure synthesis study and polarized properties of PSR J1745-2900 at 7 mm

TL;DR

This study uses high-frequency interferometric polarization observations to measure the rotation measure of pulsar J1745-2900 near the Galactic center, confirming a stable external Faraday-rotating screen and analyzing its polarized properties.

Contribution

First high-frequency (40-48 GHz) polarization observations of PSR J1745-2900, providing detailed RM measurements and insights into the Faraday-rotating environment near the Galactic center.

Findings

Measured RM of (-67±3)×10^3 rad/m^2 consistent with previous results

Detected no additional significant RM components at high frequencies

Supported the presence of a stable, external Faraday-rotating screen near the Galactic center

Abstract

We present results of interferometric polarization observations of the recently discovered magnetar J1745-2900 in the vicinity of the Galactic center. The observations were made with the Karl G. Jansky Very Large Array (VLA) on 21 February 2014 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$\pm$0.31 mJy/beam and 1.5$\pm$0.2 mJy/beam, respectively. Analysis shows a rotation measure (RM) of (-67$\pm$3)x10$^3$ rad/m$^2$, which is in a good agreement with previous measurements at longer wavelengths. These high frequency observations are sensitive to RM values of up to ~2x10$^7$ rad/m$^2$. 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 center. The Faraday corrected intrinsic electric vector position angle is 16$\pm$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.