Zusammenfassung
We use near-infrared integral field spectroscopic observations to constrain
the metallicity in a sample of 40 star forming galaxies at 3<z<5 (most of which
at z~3.4). We measure metallicities by exploiting strong emission line
diagnostics. We find that a significant fraction of star forming galaxies at
z~3.4 deviate from the Fundamental Metallicity Relation (FMR), by having a
metallicity up to a factor of ten lower than expected by the FMR. The deviation
does not correlate with the dynamical properties of the galaxy or with the
presence of interactions. To further investigate the origin of the metallicity
deviations, we also infer information on the gas content, by inverting the
Schmidt-Kennicutt relation. In agreement with recent CO observational data, we
find that, in contrast with the steeply rising trend at 0<z<2, the gas fraction
in massive galaxies remains constant, with indication of a marginal decline, at
2<z<3.5. When combined with the metallicity information, we infer that, in
order to explain both the low metallicity and gas content in z~3.4 galaxies,
both prominent outflows and massive pristine gas inflows are needed. In ten
galaxies we can also spatially resolve the metallicity distribution. We find
that generally the metallicity anticorrelates with the distribution of star
formation and with the gas surface density. We discuss these findings, both in
terms of pristine gas inflows towards the center and outflows of metal rich gas
from the center towards the external regions. (Abridged)
Nutzer