The NIRVANDELS Survey: a robust detection of α-enhancement in star-forming galaxies at z ≃ 3.4

Journal
Date Issued
2021
Author(s)
Cullen, F.
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Shapley, A. E.
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McLure, R. J.
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Dunlop, J. S.
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Sanders, R. L.
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Topping, M. W.
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Reddy, N. A.
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Amorín, R.
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Begley, R.
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Calabrò, A.
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Carnall, A. C.
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•
Cimatti, A.
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Cirasuolo, M.
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•
•
•
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Guaita, L.
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Hamadouche, M.
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Hathi, N. P.
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McLeod, D. J.
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•
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Talia, M.
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Zamorani, G.
DOI
Abstract
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 $Z \propto M_{\star }^{0.3}$. 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⋆.
Volume
505
Issue
1
Start page
903
Uri
Url
Issn Identifier
0035-8711
Ads BibCode
2021MNRAS.505..903C
Rights
open.access
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