![]() However, they are commonly found in globular clusters (GCs) which are known to form in the early Universe ( Gratton et al. The peculiar abundance ratios inferred in GN-z11 cannot be explained by classical stellar yields and standard galactic chemical evolution. Reports of other peculiar objects showing indications for high N/O exist, at low and intermediate redshift (e.g., James et al. The C/O ratio of GN-z11 is compatible with normal values but poorly constrained ( Cameron et al. This is more than one order of magnitude higher than what is usually found in low-redshift galaxies and H II regions of a similar low metallicity (12+log(O/H) ≲ 8.0), and even slightly higher than in galaxies with super-solar metallicities (e.g., Berg et al. The N/O abundance ratio in the interstellar medium (ISM) of GN-z11 derived by Cameron et al. 2023) revealed exceptional nitrogen enrichment in this high- z galaxy. The detection of unusually bright nitrogen NIII] and NIV] ultra-violet (UV) emission lines in the JWST/NIRSpec spectrum of GN-z11 ( Bunker et al. Subscribe to A&A to support open access publication. This article is published in open access under the Subscribe to Open model. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License ( ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Further studies and statistics will help differentiate the proto-GC scenario from the Wolf-Rayet scenario that we quantify with a population synthesis model, and shed more light on this peculiar object. Our model predicts the behavior of N/O, C/O, and Ne/O ratios as a function of metallicity, which can be tested if high- z objects similar to GN-z11 are detected with JWST in the future. This suggests that a proto-globular cluster hosting a SMS could be at the origin of the strong N-enrichment in GN-z11. We show that hot hydrogen-burning nucleosynthesis within supermassive stars (SMS) formed through runaway collisions can consistently explain the observed abundances ratio in GN-z11 and in GCs. We present an empirical comparison with the C, N, and O abundance ratios in Galactic globular clusters (GCs) over a large metallicity range. Unusually high N/O abundance ratios were recently reported for a very compact, intensively star-forming object GN-z11 at z = 10.6 from JWST/NIRSpec observations. ![]() Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, 08028 Barcelona, Spain Lluís Companys 23, 08010 Barcelona, Spain Institut d’Astrophysique de Paris, UMR 7095 CNRS, Sorbonne Université, 98bis Bd Arago, 75014 Paris, France ![]() Gieles 4 ,5ĭepartment of Astronomy, University of Geneva, Chemin PégVersoix, SwitzerlandĮ-mail: UMR 5277 CNRS and Université de Toulouse, 14 Av. Astronomical objects: linking to databasesĬ. ![]()
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