Investigating the conclusive phases of galaxy evolution: from star formation to quiescence

Despite the progress made towards a more comprehensive knowledge of galaxy evolution, a global picture of the mechanisms regulating the formation of stars in galaxies, of how galaxy evolutionary properties correlate with stellar masses and star formation rates (SFRs) and of the processes suppressing the star formation in galaxies and their timescales is still lacking. In this thesis work, we attempt to address some of these open questions, inspecting galaxy evolution back in cosmic time. In particular, we start from the archaeological analysis of passive local galaxies (1), reconstructing their past star formation histories. Then we take a step back towards the phase in which galaxies quench their star formation (2), defining a new methodology able to identify the quenching progenitors of passive galaxies. Finally, we move back to the star-forming phase (3), investigating the properties of high-redshift galaxies which could be the star-forming progenitors of the passive local ones. Our investigations mainly rely on the spectral analysis of galaxies. In particular, we study both the passive and star-forming phase by exploiting the information contained in the galaxy full-spectrum, whose shape depends on the properties of the underlying stellar populations. The quenching phase is instead investigated by means of emission line ratios, which are associated to the Interstellar Medium (ISM) and its ionization state during or just after the star formation has stopped.