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We use the hydrodynamic, cosmological EAGLE simulations to investigate howhot gas in haloes condenses to form and grow galaxies. We select haloes fromthe simulations that are actively cooling and study the temperature,distribution, and metallicity of their hot, cold, and transitioning `cooling'gas, placing these in context of semi-analytic models. Our selection criterialead us to focus on Milky Way-like haloes. We find the hot-gas density profilesof the haloes form a progressively stronger core over time, the nature of whichcan be captured by a beta profile that has a simple dependence on redshift. Incontrast, the hot gas that will cool over a time-step is broadly consistentwith a singular isothermal sphere. We find that cooling gas carries a few timesthe specific angular momentum of the halo and is offset in spin direction fromthe rest of the hot gas. The gas loses ~60% of its specific angular momentumduring the cooling process, generally remaining greater than that of the halo,and it precesses to become aligned with the cold gas already in the disc. Wefind tentative evidence that angular-momentum losses are slightly larger whengas cools onto dispersion-supported galaxies. We show that an exponentialsurface density profile for gas arriving on a disc remains a reasonableapproximation, but a cusp containing ~20% of the mass is always present, anddisc scale radii are larger than predicted by a vanilla Fall & Efstathioumodel. These scale radii are still closely correlated with the halo spinparameter, for which we suggest an updated prescription for galaxy formationmodels.

How to get cool in the heat: comparing analytic models of hot, cold, and cooling gas in haloes and galaxies with EAGLE