U2-2016
Host: M. Fumagalli
The survival of cold gas and dust in quasar outflows
The physical mechanisms governing quasar feedback, their observational signatures, and impact on galaxies are not yet reconciled within a unified framework. I will first contrast distinct scenarios for quasar feedback: the interaction of sub-relativistic accretion-disc winds with the interstellar medium, and the acceleration of dusty gas by radiation pressure, which operate on different spatial and temporal scales. I will show that multi-phase structure, including the formation of cool and dusty gas components, occurs naturally. However, different phases exhibit markedly different velocities, momentum fluxes, and energy fluxes, complicating the interpretation of observations. Drawing on new sub-parsec resolution hydrodynamic simulations, I will discuss the internal structure of cool cloudlets and the survival of dust grains within quasar outflows, highlighting new diagnostics of the driving mechanisms and challenging standard methods used to infer outflow properties. I will conclude by considering how the efficiency of quasar feedback may evolve with redshift and why it may weaken in faint AGN detected by JWST.