Chemo-spectrophotometric evolution of spiral galaxies - I. The model and the Milky Way

The chemical and spectrophotometric evolution of spiral galaxies is investi gated with detailed models, making use of up-to-date ingredients (like meta llicity-dependent stellar properties) and a prescription for the star forma tion rate (SFR) justified both empirically and theoretically. As a first ap plication, the model is used to describe the evolution of the Milky Way. Th e role of the adopted scheme of disc formation ('inside-out') in shaping th e various chemical and colour profiles is investigated, as well as the role of extinction. It is shown that the Solar neighbourhood does not evolve li ke the Milky Way as a whole and that one-zone models with a non-linear SFR prescription cannot be used to study the evolution of our Galaxy. Our model average SFR is shown to match well observations of external spirals.