ISO spectroscopy of luminous infrared galaxies Original Research Article

Spectroscopy from the Infrared Space Observatory ISO has for the first time provided the sensitivity to observe mid-infrared fine structure lines and PAH features in a wide range of luminous infrared galaxies. We report on observations obtained with SWS, ISOPHOT-S, and the ISOCAM CVF and show that the mid-IR spectral features are excellent diagnostic tools to distinguish starburst from active galactic nuclei activity and analyze their properties. We find that the majority of the most luminous infrared galaxies are likely predominantly powered by star formation.