JADES: the mass-metallicity relation at $z=1-10$. New calibrations, extremely metal-poor galaxies, and chemical diversity
Year: 2026
Type: preprint
Abstract: We present gas-phase metallicities of star-forming galaxies at $z=1$-10 with deep JWST/NIRSpec spectra from the JADES full data release, Dark Horse, and OASIS programmes. We stack $\sim$1500 medium-resolution spectra, yielding detections of the [OIII]$λ$4363 auroral line down to $12+\log(\mathrm{O/H})=7.0$ to derive stack-based strong-line calibrations over the metallicity range $12+\log(\mathrm{O/H})=7.0$-8.7. At a fixed metallicity, our stacks exhibit [OIII]$λ$5007/H$β$ and [OIII]$λ$5007/[OII]$λλ$3726,3729 values generally lower than calibrations based on high-$z$ individual auroral-line emitters, suggesting an observational bias towards higher excitation introduced when requiring auroral line detections in individual spectra. Based on our new calibrations, we obtain canonical mass-metallicity relations (MZRs) at z$=$1-10, identifying a decrease in metallicities from $z\sim0$ to z$\sim$4-10, without significant change in slope. Moreover, we identify 50 promising candidates of extremely metal-poor galaxies (EMPGs) with $12+\log(\mathrm{O/H})=6.7$-7.3 (1-4\% solar metallicity) at $z=1.2$-9.1. The MZRs of EMPGs are characterised by a large scatter, with those having lower metallicities generally exhibiting lower sSFRs, opposite of what expected from the local Fundamental Metallicity Relation. These results support a stochastic star-formation history involving gas consumption/ejection and metal-poor inflow, strongly affecting metallicities of low-mass galaxies. Furthermore, we identify two Little Red Dots in our EMPG candidates, both exhibiting broad H$α$ and prominent Ly$α$, offering insights into the early black-hole growth in extremely metal-poor environments.
Source: arXiv (Cornell University)
Authors: Isobe, Yuki, Curti, Mirko, Maiolino, Roberto, Duan, Qiao, McClymont, William, Puskás, Dávid, D'Eugenio, Francesco, Rinaldi, Pierluigi, Trussler, James A. A., Scholtz, Jan, Looser, Tobias J., Nelson, Erica, Ji, Xihan, Langeroodi, Danial, Tacchella, Sandro, Jones, Gareth C., Juodžbalis, Ignas, Pascalau, Robert G., Hsiao, Tiger Yu-Yang, Übler, Hannah, Baker, William M., Bunker, Andrew J., Carniani, Stefano, Charlot, Stéphane, Curtis-Lake, Emma, Geris, Sophia, Koller, Maria, Lyu, Jianwei, Robertson, Brant, Williams, Christina C., Wu, Zihao
Institutions: Osservatorio di Astrofisica e Scienza dello Spazio, National Institute for Astrophysics, University of Cambridge, Space Telescope Science Institute, Center for Astrophysics Harvard & Smithsonian, University of Colorado Boulder, Max Planck Institute for Extraterrestrial Physics, University of Copenhagen, University of Oxford, Scuola Normale Superiore, Centre National de la Recherche Scientifique, Institut d'Astrophysique de Paris, Sorbonne Université, University of Hertfordshire, University of Arizona, University of California, Santa Cruz, NSF NOIRLab
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7164418700