Direct T e-based Metallicities of z = 2–9 Galaxies with JWST/NIRSpec: Empirical Metallicity Calibrations Applicable from Reionization to Cosmic Noon
We report detections of the [O iii ] λ 4364 auroral emission line for 16 galaxies at z = 2.1–8.7, measured from JWST/NIRSpec observations obtained as part of the Cosmic Evolution Early Release Science (CEERS) survey program. We combine this CEERS sample with 9 objects from the literature at z = 4−9...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad15fc |
| _version_ | 1797333495911022592 |
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| author | Ryan L. Sanders Alice E. Shapley Michael W. Topping Naveen A. Reddy Gabriel B. Brammer |
| author_facet | Ryan L. Sanders Alice E. Shapley Michael W. Topping Naveen A. Reddy Gabriel B. Brammer |
| author_sort | Ryan L. Sanders |
| collection | DOAJ |
| description | We report detections of the [O iii ] λ 4364 auroral emission line for 16 galaxies at z = 2.1–8.7, measured from JWST/NIRSpec observations obtained as part of the Cosmic Evolution Early Release Science (CEERS) survey program. We combine this CEERS sample with 9 objects from the literature at z = 4−9 with auroral-line detections from JWST/NIRSpec and 21 galaxies at z = 1.4−3.7 with auroral-line detections from ground-based spectroscopy. We derive electron temperature ( T _e ) and direct-method oxygen abundances for the combined sample of 46 star-forming galaxies at z = 1.4−8.7. We use these measurements to construct the first high-redshift empirical T _e -based metallicity calibrations for the strong-line ratios [O iii ]/H β , [O ii ]/H β , R23 = ([O iii ]+[O ii ])/H β , [O iii ]/[O ii ], and [Ne iii ]/[O ii ]. These new calibrations are valid over 12+log(O/H) = 7.4−8.3 and can be applied to samples of star-forming galaxies at z = 2−9, leading to an improvement in the accuracy of metallicity determinations at Cosmic Noon and in the Epoch of Reionization. The high-redshift strong-line relations are offset from calibrations based on typical z ∼ 0 galaxies or H ii regions, reflecting the known evolution of ionization conditions between z ∼ 0 and z ∼ 2. Deep spectroscopic programs with JWST/NIRSpec promise to improve statistics at the low and high ends of the metallicity range covered by the current sample, as well as to improve the detection rate of [N ii ] λ 6585 and thus allow the future assessment of N-based indicators. These new high-redshift calibrations will enable accurate characterizations of metallicity scaling relations at high redshift, improving our understanding of feedback and baryon cycling in the early Universe. |
| first_indexed | 2024-03-08T08:05:42Z |
| format | Article |
| id | doaj.art-84ae4116774f49e9b0a20bb86fbb598b |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-08T08:05:42Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-84ae4116774f49e9b0a20bb86fbb598b2024-02-02T11:03:24ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-0196212410.3847/1538-4357/ad15fcDirect T e-based Metallicities of z = 2–9 Galaxies with JWST/NIRSpec: Empirical Metallicity Calibrations Applicable from Reionization to Cosmic NoonRyan L. Sanders0https://orcid.org/0000-0003-4792-9119Alice E. Shapley1https://orcid.org/0000-0003-3509-4855Michael W. Topping2https://orcid.org/0000-0001-8426-1141Naveen A. Reddy3https://orcid.org/0000-0001-9687-4973Gabriel B. Brammer4https://orcid.org/0000-0003-2680-005XDepartment of Physics and Astronomy, University of Kentucky , 505 Rose Street, Lexington, KY 40506, USA ; ryan.sanders@uky.edu; Department of Physics and Astronomy, University of California , Davis, One Shields Ave, Davis, CA 95616, USADepartment of Physics & Astronomy, University of California , Los Angeles, 430 Portola Plaza, Los Angeles, CA 90095, USASteward Observatory, University of Arizona , 933 N Cherry Avenue, Tucson, AZ 85721, USADepartment of Physics & Astronomy, University of California , Riverside, 900 University Avenue, Riverside, CA 92521, USACosmic Dawn Center (DAWN) , Denmark; Niels Bohr Institute, University of Copenhagen , Jagtvej 128, 2200 Copenhagen N, DenmarkWe report detections of the [O iii ] λ 4364 auroral emission line for 16 galaxies at z = 2.1–8.7, measured from JWST/NIRSpec observations obtained as part of the Cosmic Evolution Early Release Science (CEERS) survey program. We combine this CEERS sample with 9 objects from the literature at z = 4−9 with auroral-line detections from JWST/NIRSpec and 21 galaxies at z = 1.4−3.7 with auroral-line detections from ground-based spectroscopy. We derive electron temperature ( T _e ) and direct-method oxygen abundances for the combined sample of 46 star-forming galaxies at z = 1.4−8.7. We use these measurements to construct the first high-redshift empirical T _e -based metallicity calibrations for the strong-line ratios [O iii ]/H β , [O ii ]/H β , R23 = ([O iii ]+[O ii ])/H β , [O iii ]/[O ii ], and [Ne iii ]/[O ii ]. These new calibrations are valid over 12+log(O/H) = 7.4−8.3 and can be applied to samples of star-forming galaxies at z = 2−9, leading to an improvement in the accuracy of metallicity determinations at Cosmic Noon and in the Epoch of Reionization. The high-redshift strong-line relations are offset from calibrations based on typical z ∼ 0 galaxies or H ii regions, reflecting the known evolution of ionization conditions between z ∼ 0 and z ∼ 2. Deep spectroscopic programs with JWST/NIRSpec promise to improve statistics at the low and high ends of the metallicity range covered by the current sample, as well as to improve the detection rate of [N ii ] λ 6585 and thus allow the future assessment of N-based indicators. These new high-redshift calibrations will enable accurate characterizations of metallicity scaling relations at high redshift, improving our understanding of feedback and baryon cycling in the early Universe.https://doi.org/10.3847/1538-4357/ad15fcHigh-redshift galaxiesChemical abundancesGalaxy evolutionEmission line galaxies |
| spellingShingle | Ryan L. Sanders Alice E. Shapley Michael W. Topping Naveen A. Reddy Gabriel B. Brammer Direct T e-based Metallicities of z = 2–9 Galaxies with JWST/NIRSpec: Empirical Metallicity Calibrations Applicable from Reionization to Cosmic Noon The Astrophysical Journal High-redshift galaxies Chemical abundances Galaxy evolution Emission line galaxies |
| title | Direct T e-based Metallicities of z = 2–9 Galaxies with JWST/NIRSpec: Empirical Metallicity Calibrations Applicable from Reionization to Cosmic Noon |
| title_full | Direct T e-based Metallicities of z = 2–9 Galaxies with JWST/NIRSpec: Empirical Metallicity Calibrations Applicable from Reionization to Cosmic Noon |
| title_fullStr | Direct T e-based Metallicities of z = 2–9 Galaxies with JWST/NIRSpec: Empirical Metallicity Calibrations Applicable from Reionization to Cosmic Noon |
| title_full_unstemmed | Direct T e-based Metallicities of z = 2–9 Galaxies with JWST/NIRSpec: Empirical Metallicity Calibrations Applicable from Reionization to Cosmic Noon |
| title_short | Direct T e-based Metallicities of z = 2–9 Galaxies with JWST/NIRSpec: Empirical Metallicity Calibrations Applicable from Reionization to Cosmic Noon |
| title_sort | direct t e based metallicities of z 2 9 galaxies with jwst nirspec empirical metallicity calibrations applicable from reionization to cosmic noon |
| topic | High-redshift galaxies Chemical abundances Galaxy evolution Emission line galaxies |
| url | https://doi.org/10.3847/1538-4357/ad15fc |
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