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Abstract. Abundance gradients predicted by dissipative models of galaxy formation are studied with the aid of mass models of spherical galaxies obeying the Sersic R 1/n law in projection. The link between metallicity and stellar binding energies and angular momenta is derived from the "concentration model" by Lynden-Bell (1975) with the addition of a terminal wind and an age spread among the stellar populations of individual ellipticals. By using the calibration of the Mg 2 index as a function of metallicity and age from Single-burst Stellar Populations models, the radial profiles of Mg 2 are computed for a variety of models to illustrate the general predictions of the present approach. We also matched the observed radial profiles of Mg 2 in a sample of 11 ellipticals. We find that observations are reproduced reasonably well in our adopted approximation and require a considerable degree of dissipation and a metal yield above the solar value. A terminal wind or an age spread make it easier to fit the Mg 2 profiles of the ellipticals with shallow Mg 2 profiles in the innermost regions. However, model results (with or without an age spread) show that the exact determination of the free parameters suffers from degeneracy of their effects. Moreover, model results also suffer from the poorly known effects of non-solar abundance ratios on index Mg 2 . Other spectral indices, besides Mg 2 , and broad-band colours observed in elliptical galaxies can be examined in the same way with the present scheme; their study is postponed to a further investigation.

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Synthetic and projected properties of models of globular clusters have been computed on the basis of stellar evolution and time changes of the dynamical cluster structure. Clusters with five and eight stellar groups (each group consisting of stars with the same mass) were studied. Mass loss from evolved stars was taken into account. Observational features were obtained at ages of 10-19×109 yr. The basic importance of the horizontal- and asymptotic-branch stars was pointed out. A comparison of the results with observed data of M3 is discussed with the purpose of obtaining general indications rather than a specific fit. © 1980 D. Reidel Publishing Co

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