Properties of disk galaxies in a hierarchical formation scenario

We used galaxy evolutionary models in a hierarchical inside-out disk format ion 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 p roperties and correlations are the result of three (cosmological) initial f actors and their dispersions: the virial mass, the halo mass aggregation hi story (MAH),and the angular momentum given through the spin parameter lambd a. The MAH determines mainly the halo structure and the integral color inde xes while lambda determines mainly the surface brightness and the bulge-to- disk ratio. We calculated star formation (SF) using a gravitational instabi lity criterion and a self-regulation mechanism in the disk turbulent ISM. T he efficiency of SF in this model is almost independent from the mass. We s how that the luminosity-dependent dust absorption empirically determined by Wang & Heckman explains the observed color-magnitude and color Tully-Fishe r (TF) relations without the necessity of introducing a mass-dependent SF e fficiency. The disks in centrifugal equilibrium form within growing cold da rk matter halos with a gas accretion rate proportional to the rate of the M AH. The disks present exponential surface density and brightness profiles, negative radial color index gradients, and nearly hat rotation curves. We a lso calculated the secular formation of a bulge due to gravitational instab ilities in the stellar disk. The intensive properties of our models agree w ith the observational. data and the trends of the Hubble sequence are repro duced. The predicted infrared TF and luminosity-radius relations also agree with observations. The main shortcomings of our inside-out hierarchical mo dels are the excessive radial color gradients and the dark halo dominion in the rotation curve decompositions.