dorsal/arxiv
View SchemaNitrogen abundances in star-forming galaxies 2.2 Gyr after the Big Bang are not elevated
| Authors | D. Schaerer, Y. I. Izotov, R. Marques-Chaves, C. C. Steidel, N. Reddy, A. E. Shapley, S. Mascia, J. Chisholm, S. R. Flury, N. Guseva, T. Heckman, A. Henry, A. K. Inoue, I. Jung, H. Kusakabe, K. Mawatari, P. Oesch, G. Oestlin, L. Pentericci, N. Roy, A. Saldana-Lopez, R. Sato, E. Vanzella, A. Verhamme, B. Wang |
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| Categories | |
| ArXiv ID | 2601.06968vv1 |
| URL | https://arxiv.org/abs/2601.06968 |
| License | http://creativecommons.org/licenses/by/4.0/ |
Abstract
Using deep medium-resolution JWST rest-optical spectra of a sample of typical star-forming galaxies (Lyman break galaxies and Lyman-$\alpha$ emitters) from the LyC22 survey at $z \sim 3$, we determined the nebular abundances of N, O, and Ne relative to H for a subsample of 25 objects with the direct method, based on auroral [OIII]4363 line detections. Our measurements increases the number of accurate N/O determinations at $z \sim 2-4$ using a homogeneous approach. We found a mean value of $\log({\rm N/O})=-1.29^{+0.25}_{-0.21} $ over a metallicity range 12+log(O/H)=7.5 to 8.44. The observed N/O ratio and scatter are indistinguishable from that observed in low-z galaxies and HII regions over the same metallicity range, showing thus no redshift evolution of N/O for typical galaxies over a significant fraction of cosmic time. We also show that typical $z \sim 3$ galaxies show a similar offset in the BPT diagram as galaxies from the low-z Lyman Continuum Survey (LzLCS), when compared to the average of SDSS galaxies, and show that this offset is not due to enhanced nitrogen abundances. Our results establish a basis for future studies of the evolution of N and O at higher redshifts.
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"abstract": "Using deep medium-resolution JWST rest-optical spectra of a sample of typical star-forming galaxies (Lyman break galaxies and Lyman-$\\alpha$ emitters) from the LyC22 survey at $z \\sim 3$, we determined the nebular abundances of N, O, and Ne relative to H for a subsample of 25 objects with the direct method, based on auroral [OIII]4363 line detections. Our measurements increases the number of accurate N/O determinations at $z \\sim 2-4$ using a homogeneous approach. We found a mean value of $\\log({\\rm N/O})=-1.29^{+0.25}_{-0.21} $ over a metallicity range 12+log(O/H)=7.5 to 8.44. The observed N/O ratio and scatter are indistinguishable from that observed in low-z galaxies and HII regions over the same metallicity range, showing thus no redshift evolution of N/O for typical galaxies over a significant fraction of cosmic time. We also show that typical $z \\sim 3$ galaxies show a similar offset in the BPT diagram as galaxies from the low-z Lyman Continuum Survey (LzLCS), when compared to the average of SDSS galaxies, and show that this offset is not due to enhanced nitrogen abundances. Our results establish a basis for future studies of the evolution of N and O at higher redshifts.",
"arxiv_id": "2601.06968",
"authors": [
"D. Schaerer",
"Y. I. Izotov",
"R. Marques-Chaves",
"C. C. Steidel",
"N. Reddy",
"A. E. Shapley",
"S. Mascia",
"J. Chisholm",
"S. R. Flury",
"N. Guseva",
"T. Heckman",
"A. Henry",
"A. K. Inoue",
"I. Jung",
"H. Kusakabe",
"K. Mawatari",
"P. Oesch",
"G. Oestlin",
"L. Pentericci",
"N. Roy",
"A. Saldana-Lopez",
"R. Sato",
"E. Vanzella",
"A. Verhamme",
"B. Wang"
],
"categories": [
"astro-ph.GA"
],
"license": "http://creativecommons.org/licenses/by/4.0/",
"title": "Nitrogen abundances in star-forming galaxies 2.2 Gyr after the Big Bang are not elevated",
"url": "https://arxiv.org/abs/2601.06968",
"version": "v1"
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