CHANG-ES IX: Radio scale heights and scale lengths of a consistent
  sample of 13 spiral galaxies seen edge-on and their correlations
  The vertical halo scale height is a crucial parameter to understand the
transport of cosmic-ray electrons (CRE) and their energy loss mechanisms in
spiral galaxies. Until now, the radio scale height could only be determined for
a few edge-on galaxies because of missing sensitivity at high resolution.
  We developed a sophisticated method for the scale height determination of
edge-on galaxies. With this we determined the scale heights and radial scale
lengths for a sample of 13 galaxies from the CHANG-ES radio continuum survey in
two frequency bands.
  The sample average value for the radio scale heights of the halo are 1.1 +/-
0.3kpc in C-band and 1.4 +/- 0.7kpc in L-band. From the frequency dependence
analysis of the halo scale heights we found that the wind velocities (estimated
using the adiabatic loss time) are above the escape velocity. We found that the
halo scale heights increase linearly with the radio diameters. In order to
exclude the diameter dependence, we defined a normalized scale height which is
quite similar for all sample galaxies at both frequency bands and does not
depend on the star formation rate or the magnetic field strength. However, the
normalized scale height shows a tight anticorrelation with the mass surface
density.
  The sample galaxies with smaller scale lengths are more spherical in the
radio emission, while those with larger scale lengths are flatter. The radio
scale height depends mainly on the radio diameter of the galaxy. The sample
galaxies are consistent with an escape-dominated radio halo with convective
cosmic ray propagation, indicating that galactic winds are a widespread
phenomenon in spiral galaxies. While a higher star formation rate or star
formation surface density does not lead to a higher wind velocity, we
deceleration of CRE outflow, e.g. a lowering of the wind velocity from the
galactic disk.
