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JADES: Insights into the low-mass end of the mass-metallicity-SFR relation at 3 < z < 10 from deep JWST/NIRSpec spectroscopy

Published version
Peer-reviewed

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Type

Article

Change log

Abstract

jats:pWe analysed the gas-phase metallicity properties of a sample of low-stellar-mass (log jats:italicM</jats:italic>jats:sub⋆</jats:sub>/jats:italicM</jats:italic>jats:sub⊙</jats:sub> ≲ 9) galaxies at 3 < jats:italicz</jats:italic> < 10 observed with JWST/NIRSpec as part of the JADES programme in its deep GOODS-S tier. By combining this sample with more massive galaxies at similar redshifts from other programmes, we study the scaling relations between stellar mass (jats:italicM</jats:italic>jats:sub⋆</jats:sub>), oxygen abundance (O/H), and star-formation rate (SFR) for 146 galaxies spanning three orders of magnitude in stellar mass and out to the epoch of early galaxy assembly. We find evidence for a shallower slope at the low-mass end of the mass–metallicity relation (MZR), with 12+log(O/H) = (7.72 ± 0.02) + (0.17 ± 0.03) log(jats:italicM</jats:italic>jats:sub⋆</jats:sub>/10jats:sup8</jats:sup> jats:italicM</jats:italic>jats:sub⊙</jats:sub>), in good agreement with the MZR probed by local analogues of high-redshift systems, such as the ‘Green Pea’ and ‘Blueberry’ galaxies. The inferred slope is well matched by models including ‘momentum-driven’ supernova (SN) winds, suggesting that feedback mechanisms in dwarf galaxies (and at high jats:italicz</jats:italic>) might be different from those in place at higher masses. The evolution in the normalisation is observed to be relatively mild compared to previous determinations of the MZR at jats:italicz</jats:italic> ∼ 3 (∼0.1 − 0.2 dex across the explored mass regime). We observe a deviation from the local fundamental metallicity relation (FMR) for our sample at high redshift, especially at jats:italicz</jats:italic> > 6, with galaxies significantly less enriched than predicted given their jats:italicM</jats:italic>jats:sub⋆</jats:sub> and SFR (with a median offset in log(O/H) of ∼0.5 dex, significant at ∼5jats:italicσ</jats:italic>). These observations are consistent with an enhanced stochasticity in the gas accretion and star-formation history of high-redshift systems, prompting us to reconsider the nature of the relationship between jats:italicM</jats:italic>jats:sub⋆</jats:sub>, O/H, and SFR in the early Universe.</jats:p>

Description

Keywords

5101 Astronomical Sciences, 51 Physical Sciences

Journal Title

Astronomy and Astrophysics

Conference Name

Journal ISSN

0004-6361
1432-0746

Volume Title

684

Publisher

EDP Sciences
Sponsorship
European Research Council (695671)