amaze

AMAZE is an ESO large program aimed at determining the mass-metallicity relation in the redshift range 3 < z < 5, a crucial redshift range for galaxy evolution. The final goal of the project is to obtain a detailed description of the evolution of the mass-metallicity evolution through the cosmic epochs, to constrain galaxy evolutionary scenarios. Various physical processes may be responsible for the mass-metallicity relation (outflows/feedback, "galaxy downsizing", IMF), and each of these factors have profound implications on the formation and evolution of galaxies. So far observational constraints of the mass-metallicity relation have been obtained up to z~2.2 thanks to various deep surveys, but little work has been currently done for z>3, an epoch of major action in terms of star formation and metal enrichment of galaxies.

Observations were performed with SINFONI, the near-IR integral field spectrometer at VLT, for a total of 180 hours, distributed in three semesters. Observations have been completed in mid-2008. The targets sample consists of about 30 Lyman Break Galaxies (LBGs) and the integration times range from 3 to 7.5 hours on source. The gas metallicities are determined by means of a combination of strong line diagnostics based on Hß and [OIII]₅₀₀₇ shifted into the K band, as well as [OII]₃₇₂₇ and [NeIII]₃₈₇₀ shifted into the H band for sources at 3<z<3.7. At 4.3<z<5.2 we only rely on the [OII]/[NeIII] ratio observed in the K band. The two-dimensional spectroscopic capabilities of SINFONI are obviously exploited also to map the emission line ratios and to infer constraints on the galaxy dynamics. All of the data have been obtained and most of them have been reduced. The analysis and scientific exploitation of the data is undergoing. Preliminary scientific results on a first subsample of 9 sources has been published in Maiolino et al. (2008, A&A 488, 463): "AMAZE. I. The evolution of the mass-metallicity relation at z>3".