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- Title
Metallicity evolution, metallicity gradients, and gas fractions at z~3.4⋆,⋆⋆.
- Authors
Troncoso, P.; Maiolino, R.; Sommariva, V.; Cresci, G.; Mannucci, F.; Marconi, A.; Meneghetti, M.; Grazian, A.; Cimatti, A.; Fontana, A.; Nagao, T.; Pentericci, L.
- Abstract
We used near-infrared integral field spectroscopic observations from the AMAZE and LSD ESO programs to constrain the metallicity in a sample ost of which are at z ~ 3.4). We measured metallicities by exploiting strong emission-linf 40 star-forming galaxies at 3 < z < 5 (moe diagnostics. We found that a significant fraction of star-forming galaxies at z ~ 3.4 deviate from the fundamental metallicity relation (FMR), with a metallicity of up to a factor of ten lower than expected according to the FMR. This deviation does not correlate with the dynamical properties of the galaxy or with the presence of interactions. To investigate the origin of the metallicity deviation in more detail, we also inferred information on the gas content by inverting the Schmidt-Kennicutt relation, assuming that the latter does not evolve out to z ~ 3.4. In agreement with recent CO observational data, we found that in contrast with the steeply rising trend at 0 < z < 2, the gas fraction in massive galaxies remains constant, with an indication of a marginal decline at 2 < z < 3.5. When combined with the metallicity information, we infer that to explain 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 found that the metallicity generally anticorrelates with the distribution of star formation and with the gas surface density. We discuss these findings in terms of pristine gas inflows toward the center, and outflows of metal-rich gas from the center toward the external regions.
- Subjects
INFRARED astronomy; GALACTIC evolution; REDSHIFT; STAR formation; INFRARED spectroscopy
- Publication
Astronomy & Astrophysics / Astronomie et Astrophysique, 2014, Vol 563, p1
- ISSN
0004-6361
- Publication type
Article
- DOI
10.1051/0004-6361/201322099