The AURORA Survey: High-redshift Empirical Metallicity Calibrations from Electron Temperature Measurements at z = 2–10

@article{sanders2026aurora,
  title = {{The AURORA Survey: High-redshift Empirical Metallicity Calibrations from Electron Temperature Measurements at z = 2–10}},
  author = {Ryan L. Sanders and Alice E. Shapley and Michael W. Topping and Naveen A. Reddy and Danielle A. Berg and Ali Ahmad Khostovan and R. J. Bouwens and Gabriel Brammer and Adam C. Carnall and Fergus Cullen and Romeel Davé and J. S. Dunlop and Richard S. Ellis and N. M. Förster Schreiber and Steven R. Furlanetto and Karl Glazebrook and Garth D. Illingworth and T. Jones and Mariska Kriek and Derek J. McLeod and R. J. McLure and Desika Narayanan and Pascal A. Oesch and Anthony J. Pahl and Max Pettini and D. Schaerer and Daniel P. Stark and Charles C. Steidel and Mengtao Tang and L. Clarke and Callum T. Donnan and Emily Kehoe},
  journal = {The Astrophysical Journal},
  year = {2026},
  month = may,
  doi = {10.3847/1538-4357/ae66e2},
  url = {https://doi.org/10.3847/1538-4357/ae66e2},
  note = {CC BY},
}

TY  - JOUR
TI  - The AURORA Survey: High-redshift Empirical Metallicity Calibrations from Electron Temperature Measurements at z = 2–10
AU  - Ryan L. Sanders
AU  - Alice E. Shapley
AU  - Michael W. Topping
AU  - Naveen A. Reddy
AU  - Danielle A. Berg
AU  - Ali Ahmad Khostovan
AU  - R. J. Bouwens
AU  - Gabriel Brammer
AU  - Adam C. Carnall
AU  - Fergus Cullen
AU  - Romeel Davé
AU  - J. S. Dunlop
AU  - Richard S. Ellis
AU  - N. M. Förster Schreiber
AU  - Steven R. Furlanetto
AU  - Karl Glazebrook
AU  - Garth D. Illingworth
AU  - T. Jones
AU  - Mariska Kriek
AU  - Derek J. McLeod
AU  - R. J. McLure
AU  - Desika Narayanan
AU  - Pascal A. Oesch
AU  - Anthony J. Pahl
AU  - Max Pettini
AU  - D. Schaerer
AU  - Daniel P. Stark
AU  - Charles C. Steidel
AU  - Mengtao Tang
AU  - L. Clarke
AU  - Callum T. Donnan
AU  - Emily Kehoe
PY  - 2026
DA  - 2026/05/28
JO  - The Astrophysical Journal
DO  - 10.3847/1538-4357/ae66e2
UR  - https://doi.org/10.3847/1538-4357/ae66e2
AB  - We present detections of auroral emission lines of [O iii ], [O ii ], [S iii ], and [S ii ] in deep JWST/NIRSpec spectroscopy for 41 star-forming galaxies at z = 1.4–7.2 from the AURORA survey. We combine these new observations with 98 star-forming galaxies at z = 1.3–10.6 with detected auroral lines drawn from the literature to form a sample of 139 high-redshift galaxies with robust electron temperature and direct-method oxygen abundance determinations. This sample notably covers a wider dynamic range in metallicity than previous work, spanning 0.02–0.9 Z ⊙ . We calibrate empirical relations between 19 emission-line ratios and oxygen abundance, providing a robust tool set to infer accurate gas-phase metallicities of high-redshift galaxies when auroral lines are not detected. While calibrations based on lines of α elements (O, Ne, S, Ar) appear reliable, we find significant scatter in calibrations involving lines of N driven by a high dispersion in N/O at fixed O/H, suggesting that N-based line ratios are less reliable tracers of the oxygen abundance at high redshift. These new high-redshift calibrations are notably offset from those based on typical z ∼ 0 galaxy and H ii region samples, and are better matched by samples of extreme local galaxies that are analogs of high-redshift sources. The new metallicity calibrations presented in this work pave the way for robust studies of galaxy chemical evolution in the early Universe, leading to a better understanding of baryon cycling and galaxy formation from Cosmic Noon through the Epoch of Reionization.
SN  - 0004-637X
SN  - 1538-4357
ER  -