Star formation in external galaxies is intimately linked to questions concerning galaxy formation and evolution. Of particular interest are galaxies with star bursts. Because formation is taking place in interstellar clouds, the UV and optical stellar light is re-processed into infrared photons. The major part of the IR spectrum of starbursts is emitted from the nuclear region and the spectral energy distributions peak at about 100 µm. As their normalized spectra show similarities both in the mid infrared as well as in the far infrared (Rowan-Robinson & Crawford 1989, Roche et al. 1991), one may wonder whether starburst galaxies have a common structure.
The galactic nuclei are deeply hidden by dust so that it is necessary to observe at infrared wavelengths. Here the recent ISO mission (Kessler et al. 1996) gave new opportunities. Analyzing the data with radiative transfer models, one hopes to disclose some aspects of the true structure of the sources.
© European Southern Observatory (ESO) 1999
Online publication: November 2, 1999