The impact of AGN-radiation on the evolution of galaxies and their circumgalactic medium

• Applicant: Dr. Aura Obreja
• Subject Area: Astrophysics and Astronomy
• Term: from 2020 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 443044596

Active Galactic Nuclei (AGN) at the center of galaxies are powered by accretion episodes onto supermassive black holes depending on the gas supply in their vicinity. Even a tiny fraction of the accretion energy - if coupled efficiently to the surrounding material - has the potential to affect the evolution of the host galaxy, its halo gas (usually referred to as circumgalactic medium, CGM), and ultimately the growth and activity of the AGN itself. In particular, to reproduce the properties of massive galaxies, both analytical models and hydrodynamical cosmological simulations of galaxy formation need to include the AGN impact, usually called 'feedback'. Even though these feedback models are able to reproduce galaxy properties, they do so at the expense of providing diverse predictions for their CGM. Currently, most of these feedback models distribute a fraction of the AGN luminosity over the nearby gas as energy and/or momentum (thermal and/or kinetic feedback), without taking into account the detailed effects of the AGN radiation on the gas physics. This project thus aims to study the impact of AGN radiation on the evolution of massive galaxies and their CGM, by implementing a novel AGN radiation feedback model in two N-body hydro codes, and comparing the obtained high-resolution simulated massive structures with the latest observational data. Our approach will be twofold. First, we will compare the predictions of various AGN feedback implementations (previous implementations versus radiation) on galaxy and CGM properties. Second, the two updated N-body hydro codes will allow us to study in-depth the effects of AGN radiation on various observationally derived quantities, including the gas' thermal and ionization state, its morphology and kinematics, from galaxy to CGM and proto-cluster scales. Specifically, our project will quantitatively contrast new high resolution simulations and AGN feedback implementations against the fast growing sample of observations at redshift greater than 2, where new sensitive integral field unit spectrographs are uncovering, for the first time, gas emission on large scales surrounding massive systems.

• DFG Programme: Research Grants