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Thomson et al. have introduced the Spectral and Polarisation
in Cutouts of Extragalactic sources from the Rapid ASKAP Continuum Survey (SPICE-RACS). In their
first data release, they image 30 RACS-low fields in Stokes I, Q, U at
25 arcsecond angular resolution, across 744 to 1032 MHz with 1 MHz
spectral resolution to produce
a detailed rotation measure (RM) grid.
The images are corrected for ionospheric Faraday
rotation, primary beam attenuation, and on- and off-axis leakage. The
resulting catalogue
contains 5818 RM measurements over an area of ∼1300 square degrees:
this areal density of ~4 RMs per square degree is an increase of ∼4
times over the previous state-of-the-art. This catalogue has broad applications
for studying astrophysical magnetic fields; notably revealing
remarkable structure in the Galactic RM sky.
The image above shows the RM grid over the area selected
for the first data release:
a field at intermediate declinations allowing for
comparison with previous large-area surveys.
Much finer detail can be seen than in previous RM grid determinations.
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