STELLAR KINEMATICS OF MERGING GALAXIES - CLUES TO THE ORIGINS OF ELLIPTIC GALAXIES

There is significant evidence suggesting that mergers of galaxies prod uce elliptical galaxies. To determine whether the known kinematic prop erties of elliptical galaxies are consistent with those of their sugge sted progenitors, we have examined the stellar velocity dispersion in 11 nuclear regions within starbursting infrared-luminous galaxies. All of these galaxies are in some stage of merging. The new data are pres ented and statistically analyzed in combination with data from the lit erature. We find that the kinematic and photometric properties of thes e galaxies suggest that they are the progenitors of low-luminosity (L < L) elliptical galaxies. Dissipative collapse of gas followed by sta r formation is apparently not producing a core of high-density high-ve locity dispersion stars like those found in very bright elliptical gal axies. We suggest that only the ultraluminous infrared galaxies can po ssibly produce L ellipticals. We further present the results of popul ation synthesis models that show that intermediate-age stellar populat ions should contribute significantly to the light of merger remnants e ven after the morphological signs of merging have vanished.