Joint Astrophysical Colloquium
No smoking gun: AGN feedback in galaxy evolution
Tiago Costa (MPIA)
Thursday 10/11/2022 @ 11:30, Sala IV piano Battiferro + Remote
I will start by revisiting the original arguments laid out for the need of AGN feedback and revisit them in the light of today's theoretical understanding of galaxy evolution. I will describe advances in our grasp of the various physical mechanisms through which such feedback comes about, including momentum- and energy-driving, winds and radiation pressure and how they might couple the properties of supermassive black holes to those of their host galaxies. I will illustrate how all these processes power large-scale, multi-phase outflows and will present their observational signatures. An updated catalogue of predicted imprints of AGN activity on galaxy and black hole properties will be presented, with emphasis placed on newly-unveiled feedback effects, such as the impact of AGN on galaxy morphology, and the state of the interstellar- and circum-galactic media. Backed by results from cosmological simulations and new observations of AGN outflows, I will make the case for "energy-driven" winds as the main AGN feedback mechanism and illustrate how AGN feedback operates over a range of timescales, with the window for rapid "blow-out" episodes as the chief star formation suppressant narrowing considerably. AGN feedback, I will argue, operates cumulatively and its effect may be hard to detect directly. I will conclude with a discussion about the progress made in constraining theory with observations, discussing the pitfalls of this exercise and highlighting the new questions about the role of AGN in galaxy evolution his effort has begun to generate.