Abstract
The OVI $łambdałambda$1032, 1038\AA\ doublet emission traces collisionally
ionized gas with $T10^5.5$ K, where the cooling curve peaks for
metal-enriched plasma. This warm-hot phase is usually not well-resolved in
numerical simulations of the multiphase interstellar medium (ISM), but can be
responsible for a significant fraction of the emitted energy. Comparing
simulated OVI emission to observations is therefore a valuable test of whether
simulations predict reasonable cooling rates from this phase. We calculate OVI
$łambda$1032\AA\ emission, assuming collisional ionization equilibrium, for
our small-box simulations of the stratified ISM regulated by supernovae. We
find that the agreement is very good for our solar neighborhood model, both in
terms of emission flux and mean OVI density seen in absorption. We explore runs
with higher surface densities and find that, in our simulations, the OVI
emission from the disk scales roughly linearly with the star formation rate.
Observations of OVI emission are rare for external galaxies, but our results do
not show obvious inconsistency with the existing data. Assuming the solar
metallicity, OVI emission from the galaxy disk in our simulations accounts for
roughly 0.5\% of supernovae heating.
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