Evidences for high-velocity superwinds in starburst galaxies from ISO spectroscopy

Abstract Using a composite model which consistently accounts for the coupled effect of shocks and photoionization by hot stars, we show that high-velocity (∼400–600 km s −1 ) shocks in dense (∼500–800 cm −3 ) clouds are necessary to reproduce some critical infrared line ratios observed by ISO in some typical nearby Starburst Nucleus Galaxies. These results are in good agreement with the powerful starburst-driven superwinds and highly pressured interstellar medium observed in these starburst galaxies.