We show that the mass–metallicity relation observed in the local universe is due to a more general relation between stellar mass M★, gas‐phase metallicity and star formation rate (SFR). Local galaxies define a tight surface in this 3D space, the fundamental metallicity relation (FMR), with a small residual dispersion of ∼0.05 dex in metallicity, i.e. ∼12 per cent. At low stellar mass, metallicity decreases sharply with increasing SFR, while at high stellar mass, metallicity does not depend on SFR. High‐redshift galaxies up to z∼ 2.5 are found to follow the same FMR defined by local Sloan Digital Sky Survey (SDSS) galaxies, with no indication of evolution. In this respect, the FMR defines the properties of metal enrichment of galaxies in the last 80 per cent of cosmic time. The evolution of the mass–metallicity relation observed up to z= 2.5 is due to the fact that galaxies with progressively higher SFRs, and therefore lower metallicities, are selected at increasing redshifts, sampling different parts of the same FMR. By introducing the new quantity μα= log (M★) −α  log (SFR), with α= 0.32, we define a projection of the FMR that minimizes the metallicity scatter of local galaxies. The same quantity also cancels out any redshift evolution up to z∼ 2.5, i.e. all galaxies follow the same relation between μ0.32 and metallicity and have the same range of values of μ0.32. At z > 2.5, evolution of about 0.6 dex off the FMR is observed, with high‐redshift galaxies showing lower metallicities. The existence of the FMR can be explained by the interplay of infall of pristine gas and outflow of enriched material. The former effect is responsible for the dependence of metallicity with SFR and is the dominant effect at high redshift, while the latter introduces the dependence on stellar mass and dominates at low redshift. The combination of these two effects, together with the Schmidt–Kennicutt law, explains the shape of the FMR and the role of μ0.32. The small‐metallicity scatter around the FMR supports the smooth infall scenario of gas accretion in the local universe.

We have studied the properties of giant star forming clumps in five z~2 starforming disks with deep SINFONI AO spectroscopy at the ESO VLT 1 . The clumps reside in disk regions where the Toomre Q-parameter is below unity, consistent with their being bound and having formed from gravitational instability. Broad Hα/ [NII] line wings demonstrate that the clumps are launching sites of powerful outflows. The inferred outflow rates are comparable to or exceed the star formation rates, in one case by a factor of eight. Typical clumps may lose a fraction of their original gas by feedback in a few hundred million years, allowing them to migrate into the center. inferred gas phase oxygen abundance are broadly consistent with inside-out growing disks, and/or with inward migration of the clumps..

We compute the rate of supernovae (SNe) of different types along the Hubble sequence normalized to the near-infrared luminosity and to the stellar mass of the parent galaxies. This is made possible by the new complete catalog of near-infrared galaxy magnitudes obtained by 2MASS. We find that the rates of all SN types, including Ia, Ib/c and II, show a sharp dependence on both the morphology and the (B-K) colors of the parent galaxies and, therefore, on the star formation activity. In particular we find, with a high statistical significance, that the type Ia rate in late type galaxies is a factor ∼20 higher than in E/S0. Similarly, the type Ia rate in the galaxies bluer than B-K=2.6 is about a factor of 30 larger than in galaxies with B-K>4.1. These findings can be explained by assuming that a significant fraction of Ia events in late Spirals/Irregulars originates in a relatively young stellar component.