EVOLUTION OF SPIRAL GALAXIES .5. THE GALACTIC BULGE

We apply the multipopulation nonlinear model developed by Ferrini and coworkers to the evolution of the bulge of the Galaxy. We investigate the hypothesis of a bulge formed from the accumulation of gas by accre tion from the halo in the center of the Galaxy. We extend the properti es of phase interactions, determined in the solar neighborhood, to the bulge. The models show that bulge star formation in the bulge peaked during the early stages of the Galactic evolution and that the consequ ent element enrichment is in agreement with the observed metal abundan ces in bulge stars. The evolution of Galactic bulges and elliptical ga laxies cannot be considered equivalent.