Abstract

I will discuss our investigations into galaxy evolution, galactic-scale outflows, and the circumgalactic medium in the IllustrisTNG magnetohydrodynamical cosmological simulations. I will show how outflows sculpt the surrounding CGM , imprinting observable signatures in the gas, as well as in nearby satellite galaxy populations. I will highlight recent results from the high-resolution TNG50 simulation, which provides a unique look at the small-scale structure of cold, circumgalactic gas. In particular, I will show how this simulation produces a large abundance of small, cool gas clouds in galactic atmospheres. These clouds are found surrounding massive, quenched galaxies with high covering fraction out to large distances—the physics of their formation and survival is linked to thermal instability and the ideas of  ‘tcool/tff’, ‘precipitation’ and ‘condensation’ and may depend upon the role of magnetic fields in the CGM .