2006/08/25 by Romeel Daveé, Daveé, Romeel, Kristian Finlator +3
Physics and Astronomy · #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Solar and Space Plasma Dynamics #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0608537
8 pages, to appear in proc. "Chemodynamics 2006: From First Stars to Local Galaxies"
arxiv created 2006/08/25 · openalex publication_date 2006/08/25 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We use cosmological hydrodynamic simulations with enriched galactic outflows to compare predictions for the galaxy mass-metallicity (M*-Z) relation versus observations at z~2 from Erb et al. (2006). With no outflows, galaxies are over-enriched, indicating that outflows are required not only to suppress star formation and enrich the IGM but also to lower galaxy metal content. The observed M*-Z slope is matched both in our model without winds as well as our favored outflow model where the outflow velocity scales as the escape velocity, but is too steep in a model with constant outflow speeds. If outflows are too widespread at early times, the IGM out of which smaller galaxies form can become pre-polluted, resulting in a low-mass flattening of the M*-Z relation that is inconsistent with data. Remarkably, the same momentum-driven wind model that provides the best agreement with IGM enrichment data also yields the best agreement with the z~2 M*-Z relation, showing the proper outflow scaling and strength to match the observed slope and amplitude. In this model, the M*-Z relation evolves slowly from z=6-2; an (admittedly uncertain) extrapolation to z=0 broadly matches local M*-Z observations. Overall, the M*-Z relation provides critical constraints on galactic outflow processes during the heydey of star formation in the Universe.