  We have studied the origin of the Tully-Fisher relation by analysing
hydrodynamical simulations in a Lambda-CDM universe. We found that smaller
galaxies exhibit lower stellar masses than those predicted by the linear fit to
high mass galaxies (fast rotators), consistently with observations. In this
model, these trends are generated by the more efficient action of Supernova
feedback in the regulation of the star formation in smaller galaxies. Without
introducing scale-dependent parameters, the model predicts that the
Tully-Fisher relation bends at a characteristic velocity of around 100 km/s, in
agreement with previous observational and theoretical findings.
