Structure, dynamics and evolution of disk galaxies in a hierarchical formation scenario

Abstract

Using galaxy evolutionary models in a hierarchical formation scenario, we predict the structure, dynamics and evolution of disk galaxies in a LCDM universe. Our models include star formation and hydrodynamics of the ISM. We find that the Tully-Fisher relation (TFR) in the I and H bands is an imprint of the mass-velocity relation of the cosmological dark halos. The scatter of the TFR originates mainly from the scatter in the dark halo structure and, to a minor extension, from the dispersion of the primordial spin parameter lambda. Our models allow us to explain why low and high surface brightness galaxies have the same TFR. The disk gas fractions predicted agree with the observations. The disks formed within the growing halos have nearly exponential surface brightness and flat rotation curves. Towards high redshifts, the zero-point of the TFR in the H band increases while in the B-band it slightly decreases.