Signatures of Rapidly Rotating Stars with Chemically Homogeneous Evolution in the First Galaxies

Abstract

The James Webb Space Telescope (JWST) has revealed an unexpectedly high abundance of UV luminous galaxies at redshifts $z\gtrsim 10$, challenging `standard' galaxy formation models. This study investigates the role of rapidly rotating (massive) stars undergoing chemically homogeneous evolution (CHE) in reconciling this potential tension. These stars are more compact, hotter, and exhibit enhanced UV emission. We find that the rest-frame UV luminosity of star-forming galaxies can be significantly enhanced by a factor of $\sim 3-6$ when CHE stars above a minimum initial mass of $m_{\star ,\min }^{\mathrm{CHE}}\sim 2-10{\mathrm{M}}_{\odot }$ account for more than half of the total stellar mass following a Salpeter initial mass function. As a result, the UV luminosity functions observed at $z\sim 12-16$ can be reproduced with less extreme values of star formation efficiency and UV luminosity stochastic variability. Our results highlight the potential of CHE in explaining the UV-bright galaxy populations detected by JWST and call for future work to explore the broader astrophysical implications of CHE and its associated phenomena in the early universe, such as gamma-ray bursts, compact object binaries, and metal enrichment.

8+4 pages, 7 figures, accepted for publication in ApJL, see Figs. 2 and 3 for main results

References in corpus (14)

• Cosmic Star Formation History
• Two Remarkably Luminous Galaxy Candidates at $z\approx 10-12$ Revealed by JWST
• Efficient Formation of Massive Galaxies at Cosmic Dawn by Feedback-Free Starbursts
• Binary star progenitors of long gamma-ray bursts
• On the consistent treatment of the quasi-hydrostatic layers in hot star atmospheres
• Accelerating early massive galaxy formation with primordial black holes
• Stochastic modelling of star-formation histories II: star-formation variability from molecular clouds and gas inflow
• A Lower Bound of Star Formation Activity in Ultra-high Redshift Galaxies Detected with JWST: Implications for Stellar Populations and Radiation Sources
• Wolf-Rayet stars in the Small Magellanic Cloud: I. Analysis of the single WN stars
• Ultra-luminous X-ray sources and neutron-star-black-hole mergers from very massive close binaries at low metallicity
• Grids of stellar models with rotation: V. Models from 1.7 to 120 Msun at zero metallicity
• Evaluating chemically homogeneous evolution in stellar binaries: Electromagnetic implications -- Ionizing photons, SLSN-I, GRB, Ic-BL
• Pair-Instability Supernovae of Fast Rotating Stars
• CoReCon: an open, community-powered collection of Reionization constraints