LUMINOUS INFRARED GALAXIES

• Published in: Annual review of astronomy and astrophysics Vol. 34; no. 1; pp. 749 - 792
• Main Authors: Sanders, D. B, Mirabel, I. F
• Format: Journal Article
• Language: English
• Published: Palo Alto, CA 94303-0139 Annual Reviews 01.09.1996; 4139 El Camino Way, P.O. Box 10139; USA
• Subjects: active galactic nuclei; dust emission; luminosity function; molecular gas; starbursts
• ISSN: 0066-4146; 1545-4282
• DOI: 10.1146/annurev.astro.34.1.749

At luminosities above 10 11 , infrared galaxies become the dominant population of extragalactic objects in the local Universe ( z 0.3), being more numerous than optically selected starburst and Seyfert galaxies and quasi-stellar objects at comparable bolometric luminosity. The trigger for the intense infrared emission appears to be the strong interaction/merger of molecular gas-rich spirals, and the bulk of the infrared luminosity for all but the most luminous objects is due to dust heating from an intense starburst within giant molecular clouds. At the highest luminosities ( L ir > 10 12 ), nearly all objects appear to be advanced mergers powered by a mixture of circumnuclear starburst and active galactic nucleus energy sources, both of which are fueled by an enormous concentration of molecular gas that has been funneled into the merger nucleus. These ultraluminous infrared galaxies may represent an important stage in the formation of quasi-stellar objects and powerful radio galaxies. They may also represent a primary stage in the formation of elliptical galaxy cores, the formation of globular clusters, and the metal enrichment of the intergalactic medium.