Physics of Galactic Metals: Evolutionary Effects due to Production, Distribution, Feedback, and Interaction with Black Holes

Abstract

We ask how the inclusion of various physical heating processes due to the metal content of gas affects the evolution of central massive galaxies and compute a suite of cosmological hydrodynamical simulations that follow these systems and their supermassive black holes. We use a smoothed particle hydrodynamics code with a pressure-entropy formulation and a more accurate treatment of the metal production, turbulent diffusion, and cooling rate based on individual element abundances. The feedback models include (1) active galactic nucleus (AGN) feedback via high-velocity broad absorption line winds and Compton/photoionization heating; (2) stellar feedback from multiple processes, including powerful winds from supernovae, stellar winds from young massive stars, and AGB stars, as well as radiative heating within Str mgren spheres; and (3) additional heating effects due to the presence of metals, including grain photoelectric heating and metallicity-dependent X-ray heating by nearby accreting black holes and from the cosmic X-ray background. With a suite of zoom-in simulations of 30 halos with , we show that energy and momentum budgeted from all feedback effects generate realistic galaxy properties. We explore the detailed role of each feedback model with three additional sets of simulations with varying input physics. We show that the metal-induced heating reduces the fraction of accreted stellar material but overall has a relatively minor effect on the massive central galaxies. The inclusion of AGN feedback significantly improves the ability of our simulations to yield realistic gas and stellar properties of massive galaxies with a reasonable accreted star fraction from other galaxies.