A Uniform Analysis of Gas-phase Metallicity Evolution with 1–3 Gyr Time Sampling over the Past 12 Gyr

Authors

• Shweta Jain, University of KentuckyFollow
• Ryan L. Sanders, University of KentuckyFollow
• Ali Ahmad Khostova, University of Kentucky
• Tucker Jones, University of California, Davis
• Alice E. Shapley, University of California - Los AngelesFollow
• Naveen Reddy, University of California - RiversideFollow
• Alex M. Garcia, University of Virginia
• Paul Torrey, University of Virginia
• Alison L. Coil, University of California - San Diego

Abstract

We present a systematic investigation of the evolution of the mass–metallicity relation (MZR) and fundamental metallicity relation (FMR) using uniform metallicity diagnostics across redshifts z ∼ 0 to z ∼ 3.3. We present new Keck/Deep Imaging Multi-Object Spectrograph measurements of the [O II]λλ3726, 3729 emission line doublet for star-forming galaxies at z ∼ 1.5 with existing measurements of redder rest-optical lines from the MOSFIRE Deep Evolution Field survey. These new observations enable uniform estimation of the gas-phase oxygen abundance using ratios of the [O II], Hβ, and [O III] lines for mass-binned samples of star-forming galaxies in six redshift bins, employing strong line calibrations that account for the distinct interstellar medium ionization conditions at z < 1 and z > 1. We find that the low-mass power-law slope of the MZR remains constant over this redshift range with a value of γ = 0.28 ± 0.01, implying the outflow metal loading factor (ζ_out = (Z_out / Z_ISM) / (M_out / SFR)) scales approximately as ζ_out ∝ M_*^-0.3 out to at least z ∼ 3.3. The normalization of the MZR at 10¹⁰ M_⊙ decreases with increasing redshift at a rate of dlog(O/H) / dz = -0.11 ± 0.01 across the full redshift range. We find that any evolution of the FMR is smaller than 0.1 dex out to z ∼ 3.3. We compare to cosmological galaxy formation simulations, and find that IllustrisTNG matches our measured combination of a nearly-invariant MZR slope, rate of MZR normalization decrease, and constant or very weakly evolving FMR. This work provides the most detailed view of MZR and FMR evolution from the present day through Cosmic Noon with a fine time sampling of 1−3 Gyr, setting a robust baseline for metallicity evolution studies at z > 4 with JWST.

Document Type

Article

Publication Date

2026

Notes/Citation Information

© 2026. The Author(s). Published by the American Astronomical Society.

Digital Object Identifier (DOI)

https://doi.org/10.3847/1538-4357/ae4590

Funding Information

Some of the data presented herein were obtained at Keck Observatory, which is a private 501(c)3 nonprofit organization operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. We also wish to extend special thanks to those of Hawaiian ancestry on whose sacred mountain we are privileged to be guests. Without their generous hospitality, the work presented herein would not have been possible. We acknowledge support from NSF AAG grant AST-2307623.

Repository Citation

Jain, Shweta; Sanders, Ryan L.; Khostova, Ali Ahmad; Jones, Tucker; Shapley, Alice E.; Reddy, Naveen; Garcia, Alex M.; Torrey, Paul; and Coil, Alison L., "A Uniform Analysis of Gas-phase Metallicity Evolution with 1–3 Gyr Time Sampling over the Past 12 Gyr" (2026). Physics and Astronomy Faculty Publications. 762.
https://uknowledge.uky.edu/physastron_facpub/762