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CLASSY IX: The Chemical Evolution of the Ne, S, Cl, and Ar Elements

Arellano-Córdova, Karla; Berg, Danielle; Mingozzi, Matilde; James, Bethan; Rogers, Noah; Skillman, Evan; Cullen, Fergus; Alexander, Ryan; Amorín, Ricardo; Chisholm, John; Hayes, Matthew; Heckman, Timothy; Hernandez, Svean; Kumari, Nimisha; Leitherer, Claus; Martin, Crystal; Maseda, Michael; Nanayakkara, Themiya; Parker, Kaelee; Ravindranath, Swara; Strom, Alisson; Vincenzo, Fiorenzo; Wofford, Aida


Karla Arellano-Córdova

Danielle Berg

Matilde Mingozzi

Bethan James

Noah Rogers

Evan Skillman

Fergus Cullen

Ryan Alexander

Ricardo Amorín

John Chisholm

Matthew Hayes

Timothy Heckman

Svean Hernandez

Nimisha Kumari

Claus Leitherer

Crystal Martin

Michael Maseda

Themiya Nanayakkara

Kaelee Parker

Swara Ravindranath

Alisson Strom

Aida Wofford


To study the chemical evolution across cosmic epochs, we investigate Ne, S, Cl, and Ar abundance patterns in the COS Legacy Archive Spectroscopic SurveY (CLASSY). CLASSY comprises local star-forming galaxies (0.02 < z < 0.18) with enhanced star-formation rates, making them strong analogues to high-z star-forming galaxies. With direct measurements of electron temperature, we derive accurate ionic abundances for all elements and assess ionization correction factors (ICFs) to account for unseen ions and derive total abundances. We find Ne/O, S/O, Cl/O, and Ar/O exhibit constant trends with gas-phase metallicity for 12+log(O/H) < 8.5 but significant correlation for Ne/O and Ar/O with metallicity for 12+log(O/H) > 8.5, likely due to ICFs. Thus, applicability of the ICFs to integrated spectra of galaxies could bias results, underestimating true abundance ratios. Using CLASSY as a local reference, we assess the evolution of Ne/O, S/O, and Ar/O in galaxies at z>3, finding no cosmic evolution of Ne/O, while the lack of direct abundance determinations for S/O and Ar/O can bias the interpretation of the evolution of these elements. We determine the fundamental metallicity relationship (FMR) for CLASSY and compare to the high-redshift FMR, finding no evolution. Finally, we perform the first mass-neon relationship analysis across cosmic epochs, finding a slight evolution to high Ne at later epochs. The robust abundance patterns of CLASSY galaxies and their broad range of physical properties provide essential benchmarks for interpreting the chemical enrichment of the early galaxies observed with the JWST.


Arellano-Córdova, K., Berg, D., Mingozzi, M., James, B., Rogers, N., Skillman, E., …Wofford, A. (2024). CLASSY IX: The Chemical Evolution of the Ne, S, Cl, and Ar Elements. The Astrophysical journal, 968(2), Article 98.

Journal Article Type Article
Acceptance Date Mar 13, 2024
Online Publication Date Jun 14, 2024
Publication Date Jun 20, 2024
Deposit Date Jun 11, 2024
Publicly Available Date Jun 14, 2024
Journal Astrophysical journal
Print ISSN 0004-637X
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 968
Issue 2
Article Number 98
Keywords Galaxy abundances; Dwarf galaxies; H II regions; Gaseous nebulae; High-redshift galaxies; Compact dwarf galaxies
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Copyright Statement
© 2024. The Author(s). Published by the American Astronomical Society.
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

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