The JWST EXCELS Surv ey: gas-phase metallicity ev olution at 2 < z < 8

Abstract

The metallicities of galaxies are intrinsically sensitive to the over- ar ching pr ocesses governing g alaxy evolution. Inflows of metal- poor gas provide fuel for star formation, stars produce metals via nucleosynthesis over their lifetimes, and supernova-driven out- flows remove metal-enriched gas from galaxies (i.e. the baryon cycle; B. M. Tinsley 1980 ; K. Finlator & R. Davé2008 ; J. Tumlin- son, M. S. Peeples & J. K. Werk 2017 ). In combination with es- timat es of st ellar masses and star-formation rat es (SFRs), metal- licity measurements can be considered a fundamental tracer of the evolution and gr owth of g alaxies acr oss cosmic time. Since the launch of the James Webb Space Telescope ( JWST ), and in particular thanks to the unprecedented sensitivity of the Near- Infrar ed Spectr ograph (NIRSpec, P. Jakobsen et al. 2022 ), there has been a significant advance in the capability of measuring accurate galaxy metallicities at high r edshift ( z 2 ). We ar e now in a position to trace chemical imprints of the cosmic baryon cycle from the epoch of reionization to the local Universe.