  This study presents first results from an X-ray mini-survey carried out with
XMM-Newton to investigate the diffuse Hot Ionized Medium in the halos of nine
nearby star-forming edge-on spiral galaxies. Diffuse gaseous X-ray halos are
detected in eight of our targets, covering a wide range of star formation rates
from quiescent to starburst cases. For four edge-on spiral galaxies, namely
NGC3044, NGC3221, NGC4634, and NGC5775, we present the first published high
resolution/sensitivity detections of extended soft X-ray halos. EPIC X-ray
contour maps overlaid onto Halpha imaging data reveals that in all cases the
presence of X-ray halos is correlated with extraplanar Diffuse Ionized Gas.
Moreover, these halos are also associated with non-thermal cosmic ray halos, as
evidenced by radio continuum observations. Supplemental UV-data obtained with
the OM-telescope at 210nm show Diffuse Ionized Gas to be well associated with
UV emission originating in the underlying disk. Beside NGC891, NGC4634 is the
second non-starburst galaxy with a diffuse soft X-ray halo (|z|<4kpc). In case
of NGC3877, for which we also present the first high resolution X-ray imaging
data, no halo emission is detectable. EPIC pn spectra (0.3-12keV) of the
diffuse X-ray emission are extracted at different offset positions from the
disk, giving evidence to a significant decrease of gas temperatures, electron
densities, and gas masses with increasing distance to the plane. A comparison
between dynamical and radiative cooling time scales implies that the outflow in
all targets is likely to be sustained. We find very strong indications that
spatially correlated multi-phase gaseous halos are created by star forming
activity in the disk plane.
