Cosmic Chemical Evolution in and around Galaxies

Abstract

Using the state-of-the-art “LAOZI” cosmological hydrodynamic simulations of the stan-dard cold dark matter model with star formation feedback strength normalized to match theobserved star formation history of the universe at z = 0 - 6, we investigate the evolution ofchemical enrichment in and around galaxies at six different redshifts from redshift z = 4.0 toz = 0.62. We arrive at 4 major conclusions regarding the evolution of chemical composition within and around galaxies. 1) [Z] appears to be negatively related to radius and positively related to density. 2) The behavior of [Z] within in the virial radius is heavily dependent on mass. 3) Heavy elements are distributed more uniformly with respect to radius in more massive galaxies than in smaller galaxies. 4) Supernova blastwaves may be a source of metal-rich gas for some under-dense regions. These are both new and nontrivial findings that will provide important clues or directions of future research regarding the evolution of galaxies.Especially at the advent of upcoming observations, namely HST, JWSST, HSC, PSF and others, results from a well-refined simulations like the one used in this paper provide a great deal of observational topics.