JADES: evolution of nitrogen abundances in star-forming galaxies from z ∼ 1.5−7
Year: 2026
Type: article
Abstract: ABSTRACT We present nitrogen abundance measurements based on the low-ionization [N ii] $\lambda$6583 emission line for 588 galaxies between $1.5\lt z\lt 7.0$ from the James Webb Space Telescope Advanced Deep Extragalactic Survey. We detect the temperature-sensitive [O iii] $\lambda$4363 auroral line in 40 galaxies in our sample, affording $T_e$-based abundances for this subset. We find that the average N/O abundance ratio in this $T_e{{-}}$based low-metallicity sample is at least 0.1 dex higher than $z\sim 0$ samples. In particular, we find significant scatter towards high N/O, with five galaxies being identified with enhanced nitrogen abundances ($\log ({\rm N}/{\rm O})\gt -1.1$) at low-metallicity ($12+\log ({\rm O}/{\rm H})\lt 8.0$) from $T_e$-based measurements. Meanwhile, applying strong-line abundance measurements to the remainder of our sample reveals a further 14 candidate galaxies passing these abundance cuts, implying that around 13 per cent of $12+\log ({\rm O}/{\rm H})\lt 8.0$ galaxies at these redshifts are nitrogen-enhanced at this level. We find that N/O abundance in low-metallicity systems correlates with SFR, $\Sigma _{\rm SFR}$, and $\Sigma _{M_*}$at high redshift, while only in high-metallicity systems does a correlation with $M_*$ emerge. Despite healthy representation of these ‘moderately nitrogen-enhanced’ galaxies ($-1.1\lt \log ({\rm N}/{\rm O})\le -0.6$), no galaxies in our low-metallicity [N ii]-based sample are identified as having $\log ({\rm N}/{\rm O})\gt -0.6$, abundances that are typical of high-redshift N iii]- and N iv]-emitters. This demonstrates that the extreme nitrogen enhancements seen in some N iii]- and N iv]-emitters are only attained during the most extreme starbursts. This suggests that these elevated abundances are caused by enrichment from young massive stars in extreme environments and that the impact of this enrichment pathway is milder, though still important, for high-redshift systems on the star-forming main sequence.
Authors: Alex J Cameron, Courtney Carreira, Charlotte Simmonds, Andrew J Bunker, Aayush Saxena, Stefano Carniani, Stéphane Charlot, Jacopo Chevallard, Emma Curtis-Lake, Kevin Hainline, Ryan Hausen, Xihan Ji, Zhiyuan Ji, Benjamin D Johnson, Pierluigi Rinaldi, Brant Robertson, Jan Scholtz, Maddie S Silcock, Sandro Tacchella, James A A Trussler, Hannah Übler, Christina C Williams, Christopher N A Willmer, Chris Willott, Joris Witstok
Institutions: University of Copenhagen, University of Oxford, University of California, Santa Cruz, University of Chile, University College London, Scuola Normale Superiore, Centre National de la Recherche Scientifique, Institut d'Astrophysique de Paris, Sorbonne Université, University of Hertfordshire, University of Arizona, Johns Hopkins University, University of Cambridge, Center for Astrophysics Harvard & Smithsonian, Space Telescope Science Institute, Max Planck Institute for Extraterrestrial Physics, NSF NOIRLab, Herzberg Institute of Astrophysics
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,046
Awards: G103270039, G1812695587, Star formation in galaxies from the Epoch of Reionisation to the present day with JWST, G256731684, Finding the most distant galaxies with NIRSpec guaranteed time on the James Webb Space Telescope, G3575130984, STFC Hertfordshire 2020 DTP, G5568641063, Star formation quenching and feedback in galaxies throughout the cosmic epochs
OpenAlex ID: W7125517070