Spectroscopy with SWS and ISOPHOT-S has opened a new window for studies of the nuclei of external galaxies. We present selected results of observations of starburst galaxies and active galactic nuclei and discuss the mid-infrared extinction law. The flux ratio of high and low excitation fine structure lines and the strength of the 'PAH' emission features are mid-infrared spectroscopic tools that allow to distinguish between starburst and AGNs in heavily obscured galactic nuclei. We have verified these tools on template starburst and AGN galaxies and apply them to a sample of ultraluminous infrared galaxies, finding that most of them are predominantly powered by starburst activity.
|Number of pages||6|
|Journal||European Space Agency, (Special Publication) ESA SP|
|State||Published - 1997|
- Active galactic nuclei
- Infrared spectroscopy
- Starburst galaxies
- Ultraluminous infrared galaxies