Speaker
Description
There is no consensus on modeling the hot gas that dominates the CGM around massive galaxies
($M_{\mathrm{halo}} \sim 10^{12}-10^{13}\ \mathrm{M}_{\odot}$), with different hydrostatic equilibrium-based models predicting different thermodynamic profiles. I will present an analysis of such halos in FIRE simulations, which include realistic stellar feedback in a cosmological context but neglect AGN feedback. Inflows in these halos are generally dominated by hot gas rather than cold precipitation. I test the predictions of cooling flow models, which model inflows as bulk inflows driven by radiative cooling, against the thermodynamic profiles self-consistently realized in FIRE. I will show that cooling flows with turbulence, which contributes ~10-40% of the total pressure in the halos analyzed, describe the hot halos very well despite being highly idealized. In particular, we show that cooling flows predict entropy profiles in better agreement with the simulations than other analytic models in the literature (e.g., isothermal or isentropic models, or power-law entropy profiles motivated by non-radiative cosmological simulations). Our results indicate stellar feedback has minimal impact at the CGM scale for these halo masses. We conclude that cooling flows are a useful baseline for the hot CGM: comparison of cooling flow predictions with observations or other simulations can be used to isolate the effects of additional physics, such as AGN feedback.