Laura Magrini

There are still many open questions on galaxy formation and evolution, such as e.g. the predominance of hierarchical or monolithic processes in the galaxy formation or the temporal evolution of disk metallicity gradients. Chemical evolution models are generally able to reproduce the present- time aspect of galaxies in terms of e.g. average metallicity and radial gradient, gas and star distribution. However little is know about the past metal content and star formation history (SFH) of galaxies. Chemical abundances of stellar populations of different ages are essential to constrain the past history of nearby galaxies, both in terms of their past metal contents and of SFHs. In particular, emission-line populations as planetary nebulae (PNe) and HII regions, have similar spectroscopy instead of a very different evolutionary stage. Through optical spectroscopy of these objects we can obtain the elemental abundances of the same elements and thus put constraints on the metallicity at different epochs from the galaxy formation. By means of detailed metallicity studies of nearby galaxies, as M33, M81, IC10, NGC147, I am trying to interpret their evolution in terms of their age-metallicity relationship, of their spatial distribution of chemical abundances at different epochs, together with a continuous comparison with chemical evolution models.