We present a rest-frame UV-optical (lambda = 2500-6400 angstrom) stacked spectrum representative of massive quiescent galaxies at 1.0 < z < 1.3 with log(M-*/M-circle dot) > 10.8. The stack is constructed using VANDELS survey data, combined with new KMOS observations. We apply two independent full-spectral-fitting approaches, measuring a total metallicity [Z/H] = -0.13 +/- 0.08 with Bagpipes and [Z/H] = 0.04 +/- 0.14 with Alf, a fall of similar to 0.2-0.3 dex compared with the local universe. We also measure an iron abundance [Fe/H] = -0.18 +/- 0.08, a fall of similar to 0.15 dex compared with the local universe. We measure the alpha enhancement via the magnesium abundance, obtaining [Mg/Fe] = 0.23 +/- 0.12, consistent with galaxies of similar mass in the local universe, indicating no evolution in the average alpha enhancement of log(M-*/M-circle dot) similar to 11 quiescent galaxies over the last similar to 8 Gyr. This suggests the very high alpha enhancements recently reported for several bright z similar to 1-2 quiescent galaxies are due to their extreme masses, log(M-*/M-circle dot) greater than or similar to 11.5, in accordance with the well-known downsizing trend, rather than being typical of the z greater than or similar to 1 population. The metallicity evolution we observe with redshift (falling [Z/H], [Fe/H], constant [Mg/Fe]) is consistent with recent studies. We recover a mean stellar age of 2.5(-0.4)(+0.6) Gyr, corresponding to a formation redshift z(form) =2.4(-0.3)(+0.6) z greater than or similar to 1 massive quiescent galaxies, and, as these studies report consistent metallicities, we identify models with different star formation histories as the most likely cause. Larger spectroscopic samples from upcoming ground-based instruments will provide precise constraints on ages and metallicities at z greater than or similar to 1. Combining these with precise stellar mass functions for z > 2 quiescent galaxies from the James Webb Space Telescope will provide an independent test of formation redshifts derived from spectral fitting.

Adam C. Carnall, Ross J. McLure, James S. Dunlop, Massissilia Hamadouche, Fergus Cullen, Derek J. McLeod, et al. (2022). The Stellar Metallicities of Massive Quiescent Galaxies at 1.0 < z < 1.3 from KMOS + VANDELS. THE ASTROPHYSICAL JOURNAL, 929(2), 1-12 [10.3847/1538-4357/ac5b62].

The Stellar Metallicities of Massive Quiescent Galaxies at 1.0 < z < 1.3 from KMOS + VANDELS

Andrea Cimatti;Margherita Talia;
2022

Abstract

We present a rest-frame UV-optical (lambda = 2500-6400 angstrom) stacked spectrum representative of massive quiescent galaxies at 1.0 < z < 1.3 with log(M-*/M-circle dot) > 10.8. The stack is constructed using VANDELS survey data, combined with new KMOS observations. We apply two independent full-spectral-fitting approaches, measuring a total metallicity [Z/H] = -0.13 +/- 0.08 with Bagpipes and [Z/H] = 0.04 +/- 0.14 with Alf, a fall of similar to 0.2-0.3 dex compared with the local universe. We also measure an iron abundance [Fe/H] = -0.18 +/- 0.08, a fall of similar to 0.15 dex compared with the local universe. We measure the alpha enhancement via the magnesium abundance, obtaining [Mg/Fe] = 0.23 +/- 0.12, consistent with galaxies of similar mass in the local universe, indicating no evolution in the average alpha enhancement of log(M-*/M-circle dot) similar to 11 quiescent galaxies over the last similar to 8 Gyr. This suggests the very high alpha enhancements recently reported for several bright z similar to 1-2 quiescent galaxies are due to their extreme masses, log(M-*/M-circle dot) greater than or similar to 11.5, in accordance with the well-known downsizing trend, rather than being typical of the z greater than or similar to 1 population. The metallicity evolution we observe with redshift (falling [Z/H], [Fe/H], constant [Mg/Fe]) is consistent with recent studies. We recover a mean stellar age of 2.5(-0.4)(+0.6) Gyr, corresponding to a formation redshift z(form) =2.4(-0.3)(+0.6) z greater than or similar to 1 massive quiescent galaxies, and, as these studies report consistent metallicities, we identify models with different star formation histories as the most likely cause. Larger spectroscopic samples from upcoming ground-based instruments will provide precise constraints on ages and metallicities at z greater than or similar to 1. Combining these with precise stellar mass functions for z > 2 quiescent galaxies from the James Webb Space Telescope will provide an independent test of formation redshifts derived from spectral fitting.
2022
Adam C. Carnall, Ross J. McLure, James S. Dunlop, Massissilia Hamadouche, Fergus Cullen, Derek J. McLeod, et al. (2022). The Stellar Metallicities of Massive Quiescent Galaxies at 1.0 < z < 1.3 from KMOS + VANDELS. THE ASTROPHYSICAL JOURNAL, 929(2), 1-12 [10.3847/1538-4357/ac5b62].
Adam C. Carnall; Ross J. McLure; James S. Dunlop; Massissilia Hamadouche; Fergus Cullen; Derek J. McLeod; Ryan Begley; Ricardo Amorin; Micol Bolzonella; Marco Castellano; Andrea Cimatti; Fabio Fontanot; Adriana Gargiulo; Bianca Garilli; Filippo Mannucci; Laura Pentericci; Margherita Talia; Giovani Zamorani; Antonello Calabro; Giovanni Cresci; Nimish P. Hathi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/903890
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