Revisiting Rotation Measures from the Canadian Galactic Plane Survey: the Magnetic Field in the Disk of the Outer Galaxy

TL;DR

This paper introduces a new catalog of 2234 Faraday rotation measures from the Canadian Galactic Plane Survey, significantly enhancing the data available for studying the Galactic magnetic field in the outer disk.

Contribution

It provides a large, new set of rotation measures covering a broad region of the Galactic plane, many of which are previously unmeasured, improving the measurement density.

Findings

Increased measurement density by a factor of two.

New rotation measures for 75% of sources are previously unmeasured.

Enhanced data coverage for the Galactic magnetic field studies.

Abstract

Faraday rotation provides a valuable tracer of magnetic fields in the interstellar medium; catalogs of Faraday rotation measures provide key observations for studies of the Galactic magnetic field. We present a new catalog of rotation measures derived from the Canadian Galactic Plane Survey, covering a large region of the Galactic plane spanning 52 deg < l < 192 deg, -3 deg < b < 5 deg, along with northern and southern latitude extensions around l ~ 105 deg. We have derived rotation measures for 2234 sources (4 of which are known pulsars), 75% of which have no previous measurements, over an area of approximately 1300 square degrees. These new rotation measures increase the measurement density for this region of the Galactic plane by a factor of two.