Examinando por Autor "Reddy, N.A"

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    The NIRVANDELS Survey: a robust detection of α-enhancement in star-forming galaxies at z 3.4
    (Oxford University Press, 2021-05) Cullen, F.; Shapley, A.; McLure, R.; Dunlop, J.S; Sanders, R.L; Topping, M.W; Reddy, N.A; Amorin, R.; Begley, R.; Bolzonella, M.; Calabro, A.; Carnall, A.C; Castellano, M.; Cimatti, A.; Cirasuolo, M.; Cresci, G.; Fontana, A.; Fontanot, F.; Garilli, B.; Guaita, L.; Hamadouche, M.; Hathi, N.P; Mannucci, F.; McLeod, D. J; Pentericci, L.; Saxena, A.; Talia, M.; Zamorani, G.
    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∗. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.