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We discuss secular changes in the stellar distribution in a barred disk galaxy that may result from substantial inflows of gas. We present two- and three-dimensional N-body simulations of a disk galaxy in which we mimic the build up of gas at the center after a strong bar has formed. We show that the bar dissolves quickly and almost completely if the core mass exceeds ~5% of the combined disk and bulge mass of the galaxy model we adopt. While this result agrees with our previous single-particle orbit calculations, the exact fraction for bar dissolution may well depend on the galaxy model adopted and requires further study. Bar formation and subsequent thickening and dissolution creates an additional bulgelike stellar component from the central part of the disk. We build up the central concentration gradually, but the bar dissolves abruptly once the sustaining orbits aligned with the bar become stochastic. We discuss the predictions of such a model, including the point that barred Sc galaxies with sufficient central mass concentrations should be building bulges now. We emphasize that bulges can originate from a number of different mechanisms and discuss current evidence for bulge building and bar dissolution at both high and low redshift. It is possible that bar formation, dissolution, and bulge building may even be a recurrent process.
Norman et al. (Wed,) studied this question.