Speaker
Description
Most active galactic nuclei (AGN) are viewed through substantial columns of gas and dust whose geometry, composition, and evolution are coupled to the central accretion flow. In this talk, I will briefly review the current state of X-ray AGN surveys and their role in constraining the evolution of AGN power and obscuration across cosmic time. A fundamental ingredient is the combination of wide-area shallow surveys with pencil-beam deep fields to constrain the evolution of the AGN population through detailed population-synthesis models. I will also address some major challenges that remain, focused on the identification and characterisation of the Compton-thick AGN population. Finally, I will present the capabilities of next-generation X-ray surveys with the NewAthena Wide Field Imager, which will open new regions of the survey-area-flux-depth parameter space and enable major advances in our understanding of obscured AGN at X-ray energies.