1994A&A...288..713F

We present new evolutionary models of disk galaxies and a confrontation of these models with a sample of late type galaxies compiled from the Tully (1988) and de Vaucouleurs et al. (1991) catalogs. In the models the star formation rate (SFR) is regulated by the dissipation of the turbulent interstellar gas and the supernovae explosions (Firmani & Tutukov 1992). Several tests with the observations lead to a satisfactory agreement, among these we point out the B luminosity vs. gas mass relation and the gas surface density vs. B brightness vs. B-V color index relation. Analytical and numerical approaches reveal a secular stability of the SF in these models. The introduction of a minimum critical gas density for the SF, close to the local tidal density, makes the models unstable with repetitive SF bursts on time-scales several times the turbulent gas dissipation time. This instability is coherent in cells with sizes of several hundred parsecs and is able to explain the SF bursts in dwarf irregular galaxies, the driving force for a stochastic generation of spiral structures in disk galaxies as well as the SF coherence in density wave arms, and the SF activity in nuclei of isolated and interacting galaxies. We propose that the SF in the bright galactic nuclei radiating most part of their energy in the far infrared is regulated by the Eddington limit. The role of the SF bursts in the formation of supermassive black holes in the nuclei of disk galaxies is also discussed.