article published yes D. Schaerer author Y. I. Izotov author R. Marques-Chaves author C. C. Steidel author N. Reddy author A. E. Shapley author Sara Mascia author edaf889c-c7cd-11ef-ab1b-bb28c431bd29 J. Chisholm author S. R. Flury author N. Guseva author T. Heckman author A. Henry author A. K. Inoue author I. Jung author H. Kusakabe author K. Mawatari author P. Oesch author G. Östlin author L. Pentericci author N. Roy author A. Saldana-Lopez author R. Sato author E. Vanzella author A. Verhamme author B. Wang author JoMa department Using deep, medium-resolution, JWST rest-optical spectra of a sample of typical star-forming galaxies (Lyman-break galaxies and Lyman-α emitters) from the LyC22 survey at z ∼ 3, we determined the nebular abundances of N, O, and Ne relative to H for a subsample of 25 objects with a direct method based on auroral [O III] λ4363 line detections. Our measurements increased the number of accurate N/O determinations at z ∼ 2 − 4 using a homogeneous approach. We found a mean value of log(N/O) = −+0.25−0.21 over a metallicity range of 12 + log(O/H) = 7.56 to 8.44. The observed N/O ratio and scatter are indistinguishable from that observed in low-z galaxies and H II regions over the same metallicity range, thus showing no redshift evolution of N/O for typical galaxies over a significant fraction of cosmic time. We also show that typical z ∼ 3 galaxies have a similar offset in the BPT diagram to galaxies from the low-z Lyman Continuum Survey (LzLCS) when compared to the average of SDSS galaxies, and we demonstrate 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. https://research-explorer.ista.ac.at/download/22817/22890/2026_AstronomyAstrophysics_Schaerer.pdf application/pdfno EDP Sciences2026 eng 0004-6361 1432-0746 2601.0696810.1051/0004-6361/202556832 708 Schaerer D, Izotov YI, Marques-Chaves R, et al. Nitrogen abundances in star-forming galaxies 2.2 Gyr after the Big Bang are not elevated. <i>Astronomy &#38; Astrophysics</i>. 2026;708. doi:<a href="https://doi.org/10.1051/0004-6361/202556832">10.1051/0004-6361/202556832</a> Schaerer, D., Izotov, Y. I., Marques-Chaves, R., Steidel, C. C., Reddy, N., Shapley, A. E., … Wang, B. (2026). Nitrogen abundances in star-forming galaxies 2.2 Gyr after the Big Bang are not elevated. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202556832">https://doi.org/10.1051/0004-6361/202556832</a> D. Schaerer <i>et al.</i>, “Nitrogen abundances in star-forming galaxies 2.2 Gyr after the Big Bang are not elevated,” <i>Astronomy &#38; Astrophysics</i>, vol. 708. EDP Sciences, 2026. Schaerer, D., et al. “Nitrogen Abundances in Star-Forming Galaxies 2.2 Gyr after the Big Bang Are Not Elevated.” <i>Astronomy &#38; Astrophysics</i>, vol. 708, A242, EDP Sciences, 2026, doi:<a href="https://doi.org/10.1051/0004-6361/202556832">10.1051/0004-6361/202556832</a>. Schaerer D, Izotov YI, Marques-Chaves R, Steidel CC, Reddy N, Shapley AE, Mascia S, Chisholm J, Flury SR, Guseva N, Heckman T, Henry A, Inoue AK, Jung I, Kusakabe H, Mawatari K, Oesch P, Östlin G, Pentericci L, Roy N, Saldana-Lopez A, Sato R, Vanzella E, Verhamme A, Wang B. 2026. Nitrogen abundances in star-forming galaxies 2.2 Gyr after the Big Bang are not elevated. Astronomy &#38; Astrophysics. 708, A242. Schaerer, D., Y. I. Izotov, R. Marques-Chaves, C. C. Steidel, N. Reddy, A. E. Shapley, Sara Mascia, et al. “Nitrogen Abundances in Star-Forming Galaxies 2.2 Gyr after the Big Bang Are Not Elevated.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2026. <a href="https://doi.org/10.1051/0004-6361/202556832">https://doi.org/10.1051/0004-6361/202556832</a>. 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. Östlin, L. Pentericci, N. Roy, A. Saldana-Lopez, R. Sato, E. Vanzella, A. Verhamme, B. Wang, Astronomy &#38; Astrophysics 708 (2026). 228172026-09-06T22:01:57Z2026-09-09T12:59:51Z