Sijing Shen - October 3, 2014 The Cycle of Baryons In and Out of Galaxies and The Enrichment of the Circumgalactic and Interstellar Medium Studies of the ionization, chemical, thermodynamic, and kinematic states of gaseous material in the circumgalactic medium (CGM) hold clues to understanding the exchange of mass, metals, and energy between galaxies and their surroundings. In this talk, I will present a study of the galaxy-CGM “ecosystem” using two suites of cosmological, hydrodynamic simulations. The simulations adopt a blastwave supernova feedback model that produces large-scale galactic outflows, a star formation recipe based on a high gas density threshold, metal-dependent radiative cooling, and a model for the turbulent mixing of heavy elements. I will discuss the origins of the metals around massive, star-forming galaxies at high redshift and the contributions from accreting satellites to the total metal budget, followed by a detailed comparison of our simulations with the observed multi-phase CGM probed by absorption lines of Lyman-alpha and various metal species (e.g., Si II, C II, Mg II, Si IV, C IV and O VI). Our zoom-in simulations appear to reproduce quantitatively the spacial distribution, kinematics and the multi-phase nature of the observed circumgalactic medium. If time permits, I will further discuss how this cycle of baryons affects the ISM chemical evolution in Milky-Way like galaxies, and its implication on the enrichment history of r-process elements.