Properties of disk galaxies in a hierarchical formation scenario

We used galaxy evolutionary models in a hierarchical inside-out disk formation scenario to study the origin of the main local and global properties of disk galaxies as well as their correlations. We found that most of these properties and correlations are the result of three (cosmological) initial factors and their dispersions: the virial mass, the halo mass aggregation history (MAH),and the angular momentum given through the spin parameter lambda. The MAH determines mainly the halo structure and the integral color indexes while lambda determines mainly the surface brightness and the bulge-to-disk ratio. We calculated star formation (SF) using a gravitational instability criterion and a self-regulation mechanism in the disk turbulent ISM. The efficiency of SF in this model is almost independent from the mass. We show that the luminosity-dependent dust absorption empirically determined by Wang & Heckman explains the observed color-magnitude and color Tully-Fisher (TF) relations without the necessity of introducing a mass-dependent SF efficiency. The disks in centrifugal equilibrium form within growing cold dark matter halos with a gas accretion rate proportional to the rate of the MAH. The disks present exponential surface density and brightness profiles, negative radial color index gradients, and nearly hat rotation curves. We also calculated the secular formation of a bulge due to gravitational instabilities in the stellar disk. The intensive properties of our models agree with the observational. data and the trends of the Hubble sequence are reproduced. The predicted infrared TF and luminosity-radius relations also agree with observations. The main shortcomings of our inside-out hierarchical models are the excessive radial color gradients and the dark halo dominion in the rotation curve decompositions.