Study of the Origin of the Luminosity-Metallicity and the Stellar Mass-Metallicity Relations in Hierarchical Universes

In this work, we study the Luminosity-Metallicity relation (LMR) and the Stellar Mass -Metallicity relation (MMR) of galactic systems in a hierarhical clustering scenario. We performed numerical hydrodynamical simulations with the chemical GADGET-2 of Scannapieco et al.(2005) in a LCDM universe. We found that our simulated galactic systems reproduce the observed local LMR and its evolution in zero point and slope. The simulated MMR is also in agreement with recent observational results. From the analysis of the evolution of the MMR, we found a characteristic mass at ~10^(10.2) M_sun / h which separates two galactic populations with different astrophysical properties. More massive systems tend to have their stars formed at z > 2 and show less evolution than smaller systems. Hence, this characteristic mass is determined by the formation of the structure in a hierarchical scenario. Our results also suggest the need for important supernova feedback.