A HIGH-REDSHIFT IRAS GALAXY WITH HUGE LUMINOSITY - HIDDEN QUASAR OR PROTOGALAXY

DURING a survey intended to measure redshifts for 1,400 galaxies identified with faint sources detected by the Infrared Astronomy Satellite, we found an emission-line galaxy at a redshift of 2.286, and with the enormous far-infrared luminosity of 3 x 10(14) times that of the Sun (L.). The spectrum is very unusual, showing lines of high excitation but with very weak Lyman-alpha emission. A self-absorbed synchrotron model for the infrared energy distribution cannot be ruled out, but a thermal origin seems more plausible. A radio-quiet quasar embedded in a very dusty galaxy could account for the infrared emission, as might a starburst embedded in 1-10 x 10(9) M. of dust. The latter case demands so much dust that the object would probably be a massive galaxy in the. process of formation. In either case, this is a remarkable object, and the presence of a large amount of dust in an object of such high redshift implies the generation of heavy elements at an early cosmological epoch.