First paper based on JWST spectroscopic data

The chemical enrichment in the early Universe as probed by JWST via direct metallicity measurements at 𝑧 ∼ 8.

https://arxiv.org/pdf/2207.12375.pdf

The first public datasets already highlight the giant leap in the redshift parameter space brought to the field by the advent of rest-frame optical spectroscopy enabled by JWST, which is about to open a window on new modes of galaxy formation and evolution, helping to discover objects with properties radically different than all the other known galaxies.

We analysed the chemical properties of three z∼ 8 galaxies behind the galaxy cluster SMACS J0723.3–7327. Exploiting [OIII]𝜆4363 auroral line detections in NIRSpec spectra, we measured gas-phase metallicities ranging from extremely metal poor to about one-third solar. The three galaxies show different level of offset relative to the Fundamental Metallicity Relation, with two of them (at z∼ 7.6) being marginally consistent, while the z∼ 8.5 source deviating significantly, being probably far from the smooth equilibrium between gas flows, star formation and metal enrichment in place at later epochs.