Photometric Evolution of Galaxies in Cosmological Scenarios

The photometric evolution of galaxies in a hierarchically clustering universeis investigated. The study is based on high resolution numerical simulationswhich include the effects of gas dynamics, shock heating, radiative cooling anda heuristic star formation scheme. The outcome of the simulations is convolvedwith photometric models which enables us to predict the appearance of galaxiesin the broad band colors U, B, V, R, I and K. We demonstrate the effect of themutual interplay of the hierarchical build-up of galaxies, photometricevolution, k-correction, and intervening absorption on the appearance offorming disk galaxies at redshift one to three. We also discuss to what extendthe numerical resolution of current computer simulations is sufficient to makequantitative predictions on surface density profiles and color gradients.