We present results from the NIRVANDELS survey on the gas-phase metallicity (Zg, tracing O/H) and stellar metallicity (Z∗, tracing Fe/H) of 33 star-forming galaxies at redshifts 2.95 < z < 3.80. Based on a combined analysis of deep optical and near-IR spectra, tracing the rest-frame far-ultraviolet (FUV; 1200-2000 Å) and rest-frame optical (3400-5500 Å), respectively, we present the first simultaneous determination of the stellar and gas-phase mass-metallicity relationships (MZRs) at z ≃ 3.4. In both cases, we find that metallicity increases with increasing stellar mass (M∗) and that the power-law slope at M∗ ≤ 1010M⊙ of both MZRs scales as Z ∝ M∗0.3. Comparing the stellar and gas-phase MZRs, we present direct evidence for super-solar O/Fe ratios (i.e. α-enhancement) at z > 3, finding (O/Fe) = 2.54 ± 0.38 × (O/Fe)⊙, with no clear dependence on M∗.
|Number of pages||18|
|Journal||Monthly Notices of the Royal Astronomical Society|
|State||Published - Jul 1 2021|
Bibliographical noteFunding Information:
UK Science and Technology Facilities Council, 20173ML3WW 001 PRIN MIUR 2017, 1202007 ANID Fondecyt
© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.
- Galaxies: abundances
- Galaxies: high redshift
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science