{"DOAJ_listed":"1","oa_version":"Published Version","date_published":"2026-02-01T00:00:00Z","day":"01","tmp":{"short":"CC BY (4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png"},"article_processing_charge":"No","title":"Rapid, out-of-equilibrium metal enrichment indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy","publication_identifier":{"issn":["0004-6361"],"eissn":["1432-0746"]},"PlanS_conform":"1","OA_place":"publisher","language":[{"iso":"eng"}],"file":[{"creator":"dernst","file_size":6531719,"content_type":"application/pdf","access_level":"open_access","success":1,"file_id":"21355","date_updated":"2026-02-24T07:46:47Z","relation":"main_file","date_created":"2026-02-24T07:46:47Z","checksum":"6f5849d29ad43bee32f90152f6fc0294","file_name":"2026_AstronomyAstrophysics_Kotiwale.pdf"}],"author":[{"id":"1438afc8-1ff6-11ee-9fa6-cd4a75d66875","last_name":"Kotiwale","first_name":"Gauri","full_name":"Kotiwale, Gauri"},{"orcid":"0000-0003-2871-127X","full_name":"Matthee, Jorryt J","first_name":"Jorryt J","last_name":"Matthee","id":"7439a258-f3c0-11ec-9501-9df22fe06720"},{"first_name":"Daichi","full_name":"Kashino, Daichi","last_name":"Kashino"},{"last_name":"Vijayan","full_name":"Vijayan, Aswin P.","first_name":"Aswin P."},{"orcid":"0000-0001-5586-6950","full_name":"Torralba Torregrosa, Alberto","first_name":"Alberto","last_name":"Torralba Torregrosa","id":"018f0249-0e87-11f0-b167-cbce08fbd541"},{"first_name":"Claudia","full_name":"Di Cesare, Claudia","last_name":"Di Cesare","id":"2d002343-372f-11ef-98ec-a164d20427cb"},{"last_name":"Iani","id":"4053390a-6b68-11ef-9828-a3b8adef8d0a","first_name":"Edoardo","full_name":"Iani, Edoardo","orcid":"0000-0001-8386-3546"},{"last_name":"Bordoloi","full_name":"Bordoloi, Rongmon","first_name":"Rongmon"},{"last_name":"Leja","first_name":"Joel","full_name":"Leja, Joel"},{"last_name":"Maseda","first_name":"Michael V.","full_name":"Maseda, Michael V."},{"full_name":"Tacchella, Sandro","first_name":"Sandro","last_name":"Tacchella"},{"full_name":"Shivaei, Irene","first_name":"Irene","last_name":"Shivaei"},{"last_name":"Heintz","first_name":"Kasper E.","full_name":"Heintz, Kasper E."},{"first_name":"A. Lola","full_name":"Danhaive, A. Lola","last_name":"Danhaive"},{"last_name":"Mascia","id":"edaf889c-c7cd-11ef-ab1b-bb28c431bd29","full_name":"Mascia, Sara","first_name":"Sara"},{"last_name":"Kramarenko","id":"9a9394cb-3200-11ee-973b-f5ba2a8b16e4","orcid":"0000-0001-5346-6048","full_name":"Kramarenko, Ivan","first_name":"Ivan"},{"id":"aa14a535-50c9-11ef-b52e-e0c373d10148","last_name":"Navarrete","first_name":"Benjamín","full_name":"Navarrete, Benjamín"},{"last_name":"Mackenzie","full_name":"Mackenzie, Ruari","first_name":"Ruari"},{"last_name":"Naidu","full_name":"Naidu, Rohan P.","first_name":"Rohan P."},{"last_name":"Sobral","full_name":"Sobral, David","first_name":"David"}],"type":"journal_article","publication_status":"published","year":"2026","intvolume":"       706","publisher":"EDP Sciences","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","corr_author":"1","doi":"10.1051/0004-6361/202556597","OA_type":"diamond","acknowledgement":"We thank the anonymous referee for the insightful comments that helped improving this paper. This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Associations of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations were taken under programmes # 1243, # 1933 and # 3516. Funded by the European Union (ERC, AGENTS, 101076224). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. GK acknowledges support from the Foundation MERAC. APV acknowledge support from the Sussex Astronomy Centre STFC Consolidated Grant (ST/X001040/1).","article_type":"original","external_id":{"arxiv":["2510.19959"]},"has_accepted_license":"1","month":"02","project":[{"name":"Young galaxies as tracers and agents of cosmic reionization","grant_number":"101076224","_id":"bd9b2118-d553-11ed-ba76-db24564edfea"}],"abstract":[{"lang":"eng","text":"We aim to characterise the mass-metallicity relation (MZR) and the 3D correlation between the stellar mass, metallicity, and star formation rate (SFR) known as the fundamental metallicity relation (FMR) for galaxies at 5 < z < 7. Using ∼800 [O III] selected galaxies from deep NIRCam grism surveys, we present our stacked measurements of direct-Te metallicities, which we used to test recent strong-line metallicity calibrations. Our measured direct-Te metallicities (0.1–0.2 Z⊙ for M★ ≈ 5 × 107 − 9 M⊙, respectively) match recent JWST/NIRSpec-based results. However, there are significant inconsistencies between observations and hydrodynamical simulations. We observe a flatter MZR slope than the SPHINX20 and FLARES simulations, which cannot be attributed to selection effects. With simple models, we show that the effect of an [O III] flux-limited sample on the observed shape of the MZR is strongly dependent on the FMR. If the FMR is similar to the one in the local Universe, the intrinsic high-redshift MZR should be even flatter than is observed. In turn, a 3D relation where SFR correlates positively with metallicity at fixed mass would imply an intrinsically steeper MZR. Our measurements indicate that metallicity variations at fixed mass show little dependence on the SFR, suggesting a flat intrinsic MZR. This could indicate that the low-mass galaxies at these redshifts are out of equilibrium and that metal enrichment occurs rapidly in low-mass galaxies. However, being limited by our stacking analysis, we are yet to probe the scatter in the MZR and its dependence on SFR. Large carefully selected samples of galaxies with robust metallicity measurements can put tight constraints on the high-redshift FMR and help us to understand the interplay between gas flows, star formation, and feedback in early galaxies."}],"quality_controlled":"1","status":"public","date_updated":"2026-02-24T07:49:42Z","citation":{"ama":"Kotiwale G, Matthee JJ, Kashino D, et al. Rapid, out-of-equilibrium metal enrichment indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy. <i>Astronomy &#38; Astrophysics</i>. 2026;706. doi:<a href=\"https://doi.org/10.1051/0004-6361/202556597\">10.1051/0004-6361/202556597</a>","apa":"Kotiwale, G., Matthee, J. J., Kashino, D., Vijayan, A. P., Torralba Torregrosa, A., Di Cesare, C., … Sobral, D. (2026). Rapid, out-of-equilibrium metal enrichment indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href=\"https://doi.org/10.1051/0004-6361/202556597\">https://doi.org/10.1051/0004-6361/202556597</a>","ieee":"G. Kotiwale <i>et al.</i>, “Rapid, out-of-equilibrium metal enrichment indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy,” <i>Astronomy &#38; Astrophysics</i>, vol. 706. EDP Sciences, 2026.","short":"G. Kotiwale, J.J. Matthee, D. Kashino, A.P. Vijayan, A. Torralba Torregrosa, C. Di Cesare, E. Iani, R. Bordoloi, J. Leja, M.V. Maseda, S. Tacchella, I. Shivaei, K.E. Heintz, A.L. Danhaive, S. Mascia, I. Kramarenko, B. Navarrete, R. Mackenzie, R.P. Naidu, D. Sobral, Astronomy &#38; Astrophysics 706 (2026).","mla":"Kotiwale, Gauri, et al. “Rapid, out-of-Equilibrium Metal Enrichment Indicated by a Flat Mass-Metallicity Relation at z ∼ 6 from NIRCam Grism Spectroscopy.” <i>Astronomy &#38; Astrophysics</i>, vol. 706, A165, EDP Sciences, 2026, doi:<a href=\"https://doi.org/10.1051/0004-6361/202556597\">10.1051/0004-6361/202556597</a>.","chicago":"Kotiwale, Gauri, Jorryt J Matthee, Daichi Kashino, Aswin P. Vijayan, Alberto Torralba Torregrosa, Claudia Di Cesare, Edoardo Iani, et al. “Rapid, out-of-Equilibrium Metal Enrichment Indicated by a Flat Mass-Metallicity Relation at z ∼ 6 from NIRCam Grism Spectroscopy.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2026. <a href=\"https://doi.org/10.1051/0004-6361/202556597\">https://doi.org/10.1051/0004-6361/202556597</a>.","ista":"Kotiwale G, Matthee JJ, Kashino D, Vijayan AP, Torralba Torregrosa A, Di Cesare C, Iani E, Bordoloi R, Leja J, Maseda MV, Tacchella S, Shivaei I, Heintz KE, Danhaive AL, Mascia S, Kramarenko I, Navarrete B, Mackenzie R, Naidu RP, Sobral D. 2026. Rapid, out-of-equilibrium metal enrichment indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy. Astronomy &#38; Astrophysics. 706, A165."},"article_number":"A165","file_date_updated":"2026-02-24T07:46:47Z","scopus_import":"1","publication":"Astronomy & Astrophysics","_id":"21341","department":[{"_id":"JoMa"},{"_id":"GradSch"}],"arxiv":1,"date_created":"2026-02-22T23:01:35Z","ddc":["520"],"oa":1,"volume":706}