Abstract
We present the first part of the observations made for the Continuum Halos in
Nearby Galaxies, an EVLA Survey (CHANG-ES) project. The aim of the CHANG-ES
project is to study and characterize the nature of radio halos, their
prevalence as well as their magnetic fields, and the cosmic rays illuminating
these fields. This paper reports observations with the compact D configuration
of the Karl G. Jansky Very Large Array (VLA) for the sample of 35 nearby
edge-on galaxies of CHANG-ES. With the new wide bandwidth capabilities of the
VLA, an unprecedented sensitivity was achieved for all polarization products.
The beam resolution is an average of 9.6" and 36" with noise levels reaching
approximately 6 and 30 microJy per beam for C- and L-bands, respectively
(robust weighting). We present intensity maps in these two frequency bands (C
and L), with different weightings, as well as spectral index maps, polarization
maps, and new measurements of star formation rates (SFRs). The data products
described herein are available to the public in the CHANG-ES data release
available at www.queensu.ca/changes. We also present evidence of a trend among
galaxies with larger halos having higher SFR surface density, and we show, for
the first time, a radio continuum image of the median galaxy, taking advantage
of the collective signal-to-noise ratio of 30 of our galaxies. This image shows
clearly that a typical spiral galaxy is surrounded by a halo of magnetic fields
and cosmic rays.
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