EAS Publications Series
Volume 24, 2007CRAL-2006. Chemodynamics: From First Stars to Local Galaxies
|Page(s)||183 - 189|
|Published online||21 April 2007|
E. Emsellem, H. Wozniak, G. Massacrier, J.-F. Gonzalez, J. Devriendt and N. Champavert (eds)
EAS Publications Series, 24 (2007) 183-189
The Mass-Metallicity Relation in Cosmological Hydrodynamic Simulations
Steward Observatory, 933 N. Cherry Ave., Tucson, AZ, USA
We use cosmological hydrodynamic simulations with enriched galactic outflows to compare predictions for the galaxy mass-metallicity (M* − Z) with observations at z ≈ 2 from Erb et al. (2006). With no outflows included 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 in 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 heyday of star formation in the Universe.
© EAS, EDP Sciences, 2007
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.