The Global Magneto-Ionic Medium Survey: A Faraday Depth Survey of the
  Northern Sky Covering 1280-1750 MHz
  The Galactic interstellar medium hosts a significant magnetic field, which
can be probed through the synchrotron emission produced from its interaction
with relativistic electrons. Linearly polarized synchrotron emission is
generated throughout the Galaxy, and at longer wavelengths, modified along
nearly every path by Faraday rotation in the intervening magneto-ionic medium.
Full characterization of the polarized emission requires wideband observations
with many frequency channels. We have surveyed polarized radio emission from
the Northern sky over the the range 1280-1750 MHz, with channel width 236.8
kHz, using the John A. Galt Telescope (diameter 25.6 m) at the Dominion Radio
Astrophysical Observatory, as part of the Global Magneto-Ionic Medium Survey.
The survey covered 72% of the sky, declinations -30 to +87 degrees at all right
ascensions. The intensity scale was absolutely calibrated, based on the flux
density and spectral index of Cygnus A. Polarization angle was calibrated using
the extended polarized emission of the Fan Region. Data are presented as
brightness temperatures with angular resolution 40'. Sensitivity in Stokes Q
and U is 45 mK rms in a 1.18 MHz band. We have applied rotation measure
synthesis to the data to obtain a Faraday depth cube of resolution 150 radians
per square metre and sensitivity 3 mK rms of polarized intensity. Features in
Faraday depth up to a width of 110 radians per square metre are represented.
The maximum detectable Faraday depth is +/- 20,000 radians per square metre.
The survey data are available at the Canadian Astronomy Data Centre.
