Mid-infrared spectroscopy of obscured IRAS galaxies

Abstract

Spectra from 6 to 12 mu m are presented for the infrared galaxies NGC 1266, Arp 148, and IRAS 1713+53. Though they are not markedly luminous (<= 10(12) L_⊙), their IRAS colors are close to the colors of ultraluminous infrared galaxies, and thus indicative of heavy obscuration. The 6-12 mu m spectra are dominated by emission features of polycyclic aromatic hydrocarbon molecules at 6.2, 7.7, and 8.6 mu m. This demonstrates the existence of dust-enshrouded starbursts in those galaxies. Based on observations with the Infrared Space Observatory, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands, and the United Kingdom) with the participation of ISAS and NASA.