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| Format: | Preprint |
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2026
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2601.02463 |
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| author | Scholte, D. Cullen, F. Moustakas, J. M. Zou, H. Saintonge, A. Arellano-Cordova, K. Z. Stanton, T. M. Andrews, B. Sui, J. Aguilar, J. Ahlen, S. Bianchi, D. Brooks, D. Castander, F. J. Cheng, T. Claybaugh, T. de la Macorra, A. Dey, B. Doel, P. Douglass, K. Ferraro, S. Forero-Romero, J. E. Gaztañaga, E. Gontcho, S. Gontcho A Gutierrez, G. Joyce, R. Kremin, A. Lahav, O. Landriau, M. Guillou, L. Le Martini, P. Meisner, A. Miquel, R. Percival, W. J. Poppett, C. Prada, F. Pérez-Ràfols, I. Rossi, G. Sanchez, E. Schlegel, D. Shao, Z. Silber, J. Sprayberry, D. Tarlé, G. Weaver, B. A. |
| author_facet | Scholte, D. Cullen, F. Moustakas, J. M. Zou, H. Saintonge, A. Arellano-Cordova, K. Z. Stanton, T. M. Andrews, B. Sui, J. Aguilar, J. Ahlen, S. Bianchi, D. Brooks, D. Castander, F. J. Cheng, T. Claybaugh, T. de la Macorra, A. Dey, B. Doel, P. Douglass, K. Ferraro, S. Forero-Romero, J. E. Gaztañaga, E. Gontcho, S. Gontcho A Gutierrez, G. Joyce, R. Kremin, A. Lahav, O. Landriau, M. Guillou, L. Le Martini, P. Meisner, A. Miquel, R. Percival, W. J. Poppett, C. Prada, F. Pérez-Ràfols, I. Rossi, G. Sanchez, E. Schlegel, D. Shao, Z. Silber, J. Sprayberry, D. Tarlé, G. Weaver, B. A. |
| contents | We present the largest direct-method abundance catalogue of galaxies to date, containing measurements of 49$\,$959 star-forming galaxies at $z < 0.96$ from DESI Data Release 2. By directly measuring electron temperatures across multiple ionization zones, we provide constraints on a number of electron temperature relations finding good consistency with previous literature relations. Using these temperature measurements, we derive reliable abundances for N, O, Ne, S and Ar and measure the evolution of abundances and abundance ratios of as a function of metallicity and other galaxy properties. Our measurements include direct oxygen abundances for 49$\,$766 galaxies, leading to the discovery of the two most metal-poor galaxies in the nearby Universe, with oxygen abundances of $\rm 12+\log(O/H) = 6.77_{-0.03}^{+0.03}~\rm dex$ (1.2\% $\rm Z_{\odot}$) and $\rm 12+\log(O/H) = 6.81_{-0.04}^{+0.04}~\rm dex$ (1.3\% $\rm Z_{\odot}$). We identify a rare outlier population of 139 galaxies with high N/O ratios at low metallicity, reminiscent of galaxy abundances observed in the early Universe. We find these high N/O galaxies are more massive than typical galaxies at the same metallicity. We find the Ne/O ratio is constant at low metallicity but increases significantly at $\rm 12+log(O/H) > 8.105\pm0.004$ dex. We show that the S/O and Ar/O abundance ratios are strongly correlated, consistent with the expected additional Type Ia enrichment channel for S and Ar. In this work we present an initial survey of the key properties of the sample, with this dataset serving as a foundation for extensive future work on galaxy abundances at low redshift. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2601_02463 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Electron temperature relations and the direct N, O, Ne, S and Ar abundances of 49959 star-forming galaxies in DESI Data Release 2 Scholte, D. Cullen, F. Moustakas, J. M. Zou, H. Saintonge, A. Arellano-Cordova, K. Z. Stanton, T. M. Andrews, B. Sui, J. Aguilar, J. Ahlen, S. Bianchi, D. Brooks, D. Castander, F. J. Cheng, T. Claybaugh, T. de la Macorra, A. Dey, B. Doel, P. Douglass, K. Ferraro, S. Forero-Romero, J. E. Gaztañaga, E. Gontcho, S. Gontcho A Gutierrez, G. Joyce, R. Kremin, A. Lahav, O. Landriau, M. Guillou, L. Le Martini, P. Meisner, A. Miquel, R. Percival, W. J. Poppett, C. Prada, F. Pérez-Ràfols, I. Rossi, G. Sanchez, E. Schlegel, D. Shao, Z. Silber, J. Sprayberry, D. Tarlé, G. Weaver, B. A. Astrophysics of Galaxies We present the largest direct-method abundance catalogue of galaxies to date, containing measurements of 49$\,$959 star-forming galaxies at $z < 0.96$ from DESI Data Release 2. By directly measuring electron temperatures across multiple ionization zones, we provide constraints on a number of electron temperature relations finding good consistency with previous literature relations. Using these temperature measurements, we derive reliable abundances for N, O, Ne, S and Ar and measure the evolution of abundances and abundance ratios of as a function of metallicity and other galaxy properties. Our measurements include direct oxygen abundances for 49$\,$766 galaxies, leading to the discovery of the two most metal-poor galaxies in the nearby Universe, with oxygen abundances of $\rm 12+\log(O/H) = 6.77_{-0.03}^{+0.03}~\rm dex$ (1.2\% $\rm Z_{\odot}$) and $\rm 12+\log(O/H) = 6.81_{-0.04}^{+0.04}~\rm dex$ (1.3\% $\rm Z_{\odot}$). We identify a rare outlier population of 139 galaxies with high N/O ratios at low metallicity, reminiscent of galaxy abundances observed in the early Universe. We find these high N/O galaxies are more massive than typical galaxies at the same metallicity. We find the Ne/O ratio is constant at low metallicity but increases significantly at $\rm 12+log(O/H) > 8.105\pm0.004$ dex. We show that the S/O and Ar/O abundance ratios are strongly correlated, consistent with the expected additional Type Ia enrichment channel for S and Ar. In this work we present an initial survey of the key properties of the sample, with this dataset serving as a foundation for extensive future work on galaxy abundances at low redshift. |
| title | Electron temperature relations and the direct N, O, Ne, S and Ar abundances of 49959 star-forming galaxies in DESI Data Release 2 |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2601.02463 |