Joint Astrophysical Colloquium
Simulating galaxies from dwarfs to clusters -- the diverse and far-reaching effects of super massive black holes
Annalisa Pillepich (MPIA Heidelberg)
Thursday 22/01/2026 @ 11:30, Sala Antonio Sollima (IV piano Battiferro)
Over the past two decades, it has become clear that energetic feedback from supermassive black holes (SMBHs) is a fundamental ingredient in our models of galaxy formation and evolution. From quenching star formation in massive galaxies to regulating the properties of the circumgalactic and intracluster media, SMBH-driven processes manifest across a wide range of scales and environments. In this talk, I will present recent advances in our understanding of the diverse and far-reaching effects of SMBH feedback, as revealed by state-of-the-art cosmological simulations. I will begin by introducing the simulations themselves — in particular, the IllustrisTNG project, which I have co-led and developed, and which has become a benchmark in extragalactic modeling for both observers and theorists alike. I will also introduce the TNG-Cluster simulation suite, a spin-off project focusing on the most massive galaxy clusters. Using results from IllustrisTNG and its successors, I will demonstrate how a unified set of physical models can simultaneously reproduce realistic galaxy populations while predicting the thermodynamical, ionization, and chemical properties of cosmic gas on halo and intergalactic scales. I will highlight how feedback leaves its most direct and distinctive imprints not on the stars, but on the surrounding gas — influencing its temperature, kinematics, metal enrichment, and X-ray emission. In particular, I will contrast the effects of SMBH feedback in star-forming versus quiescent galaxies, highlighting how their gaseous atmospheres bear the signatures of these energetic processes. I will conclude by providing a diversity of insights and predictions for the gaseous haloes of galaxies spanning five orders of magnitude in mass, illustrating how SMBH feedback shapes the circumgalactic, intragroup, and intracluster media.