1998/08/28 by D. Lutz, R. Genzel, Lutz, D. +9
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.astro-ph/9808330
openalex publication_date 1998/08/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We have obtained ISOPHOT-S low resolution mid-infrared spectra of a sample of 60 Ultraluminous Infrared Galaxies (ULIRGs). We use the strength of the `PAH' mid-infrared features as a discriminator between starburst and AGN activity, and to probe for evolutionary effects. We focus on the fact that observed ratios of PAH features in ULIRGs differ slightly from those in lower luminosity starbursts. We suggest that such PAH ratio changes relate to the conditions in the interstellar medium in these galaxies, and in particular to extinction.