Luminosity profiles of merger remnants

Using published luminosity and molecular gas profiles of the late-stage mer gers NGC 3921, NGC 7252, and Arp 220, we examine the expected luminosity pr ofiles of the evolved merger remnants, especially in light of the massive C O complexes that are observed in their nuclei. For NGC 3921 and NGC 7252, w e predict that the resulting luminosity profiles will be characterized by a n r(1/4) law. In view of previous optical work on these systems, it seems l ikely that they will evolve into normal elliptical galaxies as regards thei r optical properties. Due to a much higher central molecular gas column den sity, Arp 220 might not evolve such a "seamless" light profile. We conclude that ultraluminous infrared mergers such as Arp 220 either evolve into ell iptical galaxies with anomalous luminosity profiles or do not produce many low-mass stars out of their molecular gas complexes.