Warm ultraluminous galaxies in the IRAS survey - The transition from galaxy to quasar?

Abstract

Of 90 extragalactic objects chosen from the IRAS catalog on the basis of brightness at 60 μm and "warm" infrared color [fν(25 μm)/fν(60 μm) >0.2], 12 have luminosities characteristic of quasars. These 12 ultraluminous objects have Seyfert spectra, and nine of them show morphological evidence for recent collisions or mergers - they plausibly represent a transition stage between cooler ultraluminous infrared galaxies and optical quasars.