Semi-analytic modelling of Pop. III star formation and metallicity evolution – I. Impact on the UV luminosity functions at z = 9–16

Emanuele M. Ventura*, Yuxiang Qin, Sreedhar Balu, J. B.Stuart Wyithe

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

We implemented Population III (Pop. III) star formation in mini-haloes within the Meraxes semi-analytic galaxy formation and reionization model, run on top of a N-body simulation with L = 10 h(-1) cMpc with 20483 particles resolving all dark matter haloes down to the mini-haloes (similar to 10(5) M-circle star). Our modelling includes the chemical evolution of the IGM, with metals released through supernova-driven bubbles that expand according to the Sedov-Taylor model. We found that SN-driven metal bubbles are generally small, with radii typically of 150 ckpc at z = 6. Hence, the majority of the first galaxies are likely enriched by their own star formation. However, as reionization progresses, the feedback effects from the UV background become more pronounced, leading to a halt in star formation in low-mass galaxies, after which external chemical enrichment becomes more relevant. We explore the sensitivity of the star formation rate density and stellar mass functions to the unknown values of free parameters. We also discuss the observability of Pop. III dominated systems with JWST, finding that the inclusion of Pop. III galaxies can have a significant effect on the total UV luminosity function at z = 12-16. Our results support the idea that the excess of bright galaxies detected with JWST might be explained by the presence of bright top-heavy Pop. III dominated galaxies without requiring an increased star formation efficiency.
Original languageEnglish
Pages (from-to)628-646
Number of pages19
JournalMonthly Notices of the Royal Astronomical Society
Volume529
Issue number1
DOIs
Publication statusPublished - 27 Feb 2024

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