We interpret the peculiar supersolar nitrogen abundance recently reported by the James Webb Space Telescope observations for GN-z11 (z = 10.6) using our state-of-the-art chemical evolution models. The observed CNO ratios can be successfully reproduced—independently of the adopted initial mass function, nucleosynthesis yields, and presence of supermassive (>1000Me) stars—if the galaxy has undergone an intermittent star formation history with a quiescent phase lasting ∼100 Myr, separating two strong starbursts. Immediately after the second burst, Wolf–Rayet stars (up to 120Me) become the dominant enrichment source, also temporarily (<1 Myr) enhancing particular elements (N, F, Na, and Al) and isotopes (13 C and 18 O). Alternative explanations involving (i) single burst models, also including very massive stars and/or pair-instability supernovae, or (ii) pre-enrichment scenarios fail to match the data. Feedback-regulated, intermittent star formation might be common in early systems. Elemental abundances can be used to test this hypothesis and to get new insights on nuclear and stellar astrophysics.

Rapid Chemical Enrichment by Intermittent Star Formation in GN-z11

Ferrara, Andrea
2024

Abstract

We interpret the peculiar supersolar nitrogen abundance recently reported by the James Webb Space Telescope observations for GN-z11 (z = 10.6) using our state-of-the-art chemical evolution models. The observed CNO ratios can be successfully reproduced—independently of the adopted initial mass function, nucleosynthesis yields, and presence of supermassive (>1000Me) stars—if the galaxy has undergone an intermittent star formation history with a quiescent phase lasting ∼100 Myr, separating two strong starbursts. Immediately after the second burst, Wolf–Rayet stars (up to 120Me) become the dominant enrichment source, also temporarily (<1 Myr) enhancing particular elements (N, F, Na, and Al) and isotopes (13 C and 18 O). Alternative explanations involving (i) single burst models, also including very massive stars and/or pair-instability supernovae, or (ii) pre-enrichment scenarios fail to match the data. Feedback-regulated, intermittent star formation might be common in early systems. Elemental abundances can be used to test this hypothesis and to get new insights on nuclear and stellar astrophysics.
2024
Settore FIS/05 - Astronomia e Astrofisica
Chemical abundances (224); Galaxy formation (595); Galaxy evolution (594); Stellar nucleosynthesis (1616); Interstellar abundances (832); Galaxy abundances (574); Wolf-Rayet stars (1806); Population III stars (1285)
   The Interstellar Medium of High Redshift Galaxies
   INTERSTELLAR
   European Commission
   Horizon 2020 Framework Programme
   740120
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/138802
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