Self-ionizing galactic winds
  We present hydrodynamical simulations of galactic winds from star-forming
galaxies including non-equilibrium ionization and frequency-dependent radiative
transfer, processes that have remained largely unaccounted for in galactic wind
studies. We consider radiation from massive stars, the metagalactic UV/X-ray
background, and the self-radiation of the supernovae heated gas. We compare our
results to classical galactic wind solutions and show the importance of our
newly included physical processes toward observations of ions such as O III, O
VI, O VII and O VIII plus the observable soft X-ray spectra. Non-equilibrium
ionization is reflected in over-ionized gas compared to equilibrium solutions,
leading to much enhanced column densities of highly ionized species. The wind
produces excess soft X-ray ($E\gtrsim 100$ eV) radiation that is several orders
of magnitude higher compared to the metagalactic background. This radiation
ionizes the higher ions (such as O VII) somewhat, but affects the lower ions
(such as O III) significantly. We predict that the observable X-ray spectra
should contain the signatures of such non-equilibrium effects, especially in
X-ray lines such as O VII and O VIII. Simple estimates suggest that both the
temperature and density of the winds may be overestimated by factors of a few
to almost 2 orders of magnitude using simple equilibrium models. We conclude
that both the non-equilibrium ionization and the radiation from the wind itself
need to be considered for proper modeling of the optical/UV/X-ray emitting
plasma in galactic winds.
