We correlate the ROSAT 1/4 keV all-sky survey with the Leiden/Dwingeloo HI
survey, looking for soft X-ray signatures of prominent high-velocity-cloud
(HVC) complexes. We study the transfer of 1/4 keV photons through the
interstellar medium in order to distinguish variations in the soft X-ray
background (SXRB) intensity caused by photoelectric absorption effects from
those due to excess X-ray emission. The X-ray data are modelled as a
combination of emission from the Local Hot Bubble (LHB) and emission from a
distant plasma in the galactic halo and extragalactic sources. The X-ray
radiation intensity of the galactic halo and extragalactic X-ray background is
modulated by the photoelectric absorption of the intervening galactic
interstellar matter. We show that large- and small-scale intensity variations
of the 1/4 keV SXRB are caused by photoelectric absorption which is
predominantly traced by the total N(HI) distribution. The extensive coverage of
the two surveys supports evidence for a hot, X-ray emitting corona. We show
that this leads to a good representation of the SXRB observations. For four
large areas on the sky, we search for regions where the modelled and observed
X-ray emission differ. We find that there is excess X-ray emission towards
regions near HVC complexes C, D, and GCN. We suggest that the excess X-ray
emission is positionally correlated with the high-velocity clouds. Some lines
of sight towards HVCs also pass through significant amounts of
intermediate-velocity gas, so we cannot constrain the possible role played by
IVC gas in these directions of HVC and IVC overlap, in determining the X-ray
excesses.Comment: 16 pages, 8 figures, accepted for publication in Astronomy &
Astrophysics main journa