It is thought that a super massive black hole resides in the centre of each galaxy. Some galaxies show signs of nuclear activity related to accretion of material onto this super massive black hole, and the central regionsof these galaxies associated with this phenomenon are called active galactic nuclei. This accretion is also associated with outflows. Cátia Silva studies these AGN outflows using a spectral timing approach. The aim is to characterize the physical properties of the outflows as they are of crucial importance to the understanding of large-scale structure formation and evolution.