An atlas of mid-infrared spectra of galaxy nuclei

Abstract

The spectral energy distributions are presented for 60 galaxies for which 8-13 μm, and in some cases 17-23 μm, spectra have been obtained. These IR bright galaxies are discussed in terms of their spectral properties in the mid-IR and the relationship with their far-IR properties. Almost all of the galaxies can be placed in one of three classes on the basis of their 8-13 μm spectra : those dominated by the family of narrow bands between 3-13 μm, those with featureless continua and those that display the silicate absorption band. H II region galaxy nuclei, i.e., those which contain powerful nuclear H II regions and whose mid-IR spectra are dominated by emission in the family of narrow emission bands display little dispersion in their IR properties.