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 heightis 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 heightcould only be determined for a few edge-on galaxies because of missing sensitivity at high resolution. We developed a sophisticated method for the scale heightdetermination of edge-on galaxies. With this we determined the scale heightsand radial scalelengths 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 heightsof the haloare 1.1 +/- 0.3kpc in C-band and 1.4 +/- 0.7kpc in L-band. From the frequency dependence analysisof the halo scale heightswe found that the wind velocities (estimated using the adiabatic loss time) are above the escape velocity. We found that the halo scale heightsincrease linearly with the radio diameters. In order to exclude the diameter dependence, we defined a normalized scale heightwhich is quite similar for all sample galaxies at both frequency bands and does not depend on the star formationrate or the magnetic field strength. However, the normalized scale heightshows a tight anticorrelation with the mass surface density. The sample galaxies with smaller scalelengths are more spherical in the radio emission, while those with larger scalelengths are flatter. The radio scale heightdepends mainly on the radio diameter of the galaxy. The sample galaxies are consistent with an escape-dominated radio halowith convective cosmic ray propagation, indicating that galactic winds are a widespread phenomenon in spiral galaxies. While a higher star formationrate or star formationsurface 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.