The role of active galactic nuclei (AGN) in the formation and evolution of galaxies is still not well established. Some authors claim that AGN are key in quenching star
formation in their host galaxies through so-called AGN feedback, which has been invoked to explain the well-established correlations between supermassive-black-hole (SMBH)
mass and host-galaxy properties. In order to understand the importance of AGN feedback in the star-formation histories of galaxies, it is necessary
to study how the star formation rate (SFR) in active galaxies evolves with redshift.