New constraints on stellar feedback through [O III] emission: interpreting ALMA and JWST observations with SPICE simulations

Abstract

ALMA and JWST have recently detected emission lines from the interstellar medium of star-forming galaxies during the Epoch of Reionization, reaching redshifts up to z = 14. Among these, [OIII] lines provide a powerful diagnostic of metal enrichment, gas ionization, and the impact of stellar feedback in galaxies at z > 6. Modeling this emission in cosmological simulations is challenging due to the wide range of spatial scales and physical processes involved. To address this, we have developed a post-processing pipeline that implements a sub-grid model for [OIII] line emission within the SPICE radiation-hydrodynamical simulations. These simulations explore three supernova feedback prescriptions: bursty-sn, smooth-sn, and the hypernova-based hyper-sn. We investigate how these feedback models affect metal enrichment, the neutral gas fraction, and the size and morphology of ionized halos traced by [OIII] emission in both the optical and far-infrared. We find that [OIII] emission predominantly originates from gas that is both shock-heated and radiatively ionized. We also examine the mass-metallicity relation and the correlation between neutral gas fraction and [OIII] luminosity. Our results show that the bursty-sn model efficiently ionizes gas but enriches galaxies less effectively by z = 5, leading to fewer bright [OIII] emitters compared to the smooth-sn model. Both bursty-sn and hyper-sn produce suppressed luminosity functions. Spatially resolved [OIII] emission further indicates that smooth-sn tends to generate more compact galaxies and slightly higher V/{\sigma} values, although there is significant overlap between models. Overall, our findings demonstrate that [OIII] emission is a sensitive tracer of stellar feedback at high redshift and highlight the importance of observations probing fainter luminosities, where feedback effects are strongest.