CHANG-ES XVII: H-alpha Imaging of Nearby Edge-on Galaxies, New SFRs, and
  an Extreme Star Formation Region -- Data Release 2
  We present new narrow-band H-alpha imaging for 24 nearby edge-on galaxies in
the CHANG-ES survey. We use the images in conjunction with WISE 22 micron
imaging of the sample to estimate improved star formation rates (SFRs) using
the updated recipe from Vargas et al. (2018). We explore correlations between
the updated star formation properties and radio continuum scale heights, scale
lengths, and diameters, measured in Krause et al. (2018). We find a newly
discovered correlation between SFR and radio scale height that did not exist
using mid-IR only SFR calibrations. This implies that a mid-IR extinction
correction should be applied to SFR calibrations when used in edge-on galaxies,
due to attenuation by dust. The updated SFR values also show newly discovered
correlations with radio scale length and radio diameter, implying that the
previously-measured relationship between radio scale height and radio diameter
originates from star formation within the disk. We also identify a region of
star formation located at extreme distance from the disk of NGC 4157, possibly
ionized by a single O5.5 V star. This region is spatially coincident with an
XUV disk feature, as traced by GALEX NUV imaging. We theorize that the star
formation feature arose due to gravitational instability within gas from an
accretion event. New H-alpha images from this work can be found at the CHANG-ES
data release web site, https://www.queensu.ca/changes.
