  Starburst galaxies are generally associated with extended X-ray and radio
halos, giving a clear hint of an outflow of gas and relativistic particles from
the disk into the halo. The driving agents are, not surprisingly, active star
forming regions, injecting hot gas and cosmic rays generated by supernova
remnant and superbubble shock waves. The dynamics of the outflow and the
thermal evolution of the plasma are strongly coupled, and therefore a
self-consistent model is necessary for a satisfactory description. Since the
plasma temperature is between one and a few million Kelvin, the halo is most
conspicuous in soft X-rays. It will be shown that X-ray data obtained recently
with XMM-Newton EPIC pn bear clear spectral signatures that are in strong
disagreement with an isothermal halo in collisional ionization equilibrium
(CIE). Instead a temperature structure in X-ray halos is observed. It will be
demonstrated that a galactic wind outflow model in which the non-equilibrium
ionization structure is calculated self-consistently can give a satisfactory
and physical explanation for the X-ray spectral characteristics, e.g. in case
of the local starburst galaxy NGC 3079. In particular, high subsolar
abundances, that have been reported from X-ray observations in some cases, are
shown to be artefacts of CIE spectral fit models. It is found that spectral
models are strongly constrained by the presence of diagnostic lines such as
OVII and OVIII as well as Fe-L line complexes. Thus a detailed spectral X-ray
model will help to provide important galactic wind parameters, such as mass
loss rate and velocity profile, which may also serve as valuable input for
galactic outflows in the early universe.
