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

Of 90 extragalactic objects chosen from the I RAS catalog on the basis of brightness at 60 m and "warm" infrared color [f.(25 m)lfv(60 m) > 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.