Metallicities of Five z > 5 Emission-line Galaxies in SMACS 0723 Revealed by JWST

Abstract JWST’s Early Release Observations of the lensing cluster SMACS J0723.3–7327 have given an unprecedented spectroscopic look into high-redshift universe. These observations reveal five galaxies at z > 5. All detectable [O iii ] λ 4363 line emission, indicating that these high temperatures and low metallicities they are highly star-forming. In recent work, been studied using various techniques. Here we summarize compare previous results, as well perform our own measurements improved methodologies optimize extraction emission lines. particular, use simultaneous fitting a fixed Balmer decrement correction, novel footprint measurement lines in 2D spectra, to produce higher-fidelity ratios less sensitive calibration systematic effects. We then those ≲ 1 with rest-frame equivalent widths H β , finding may be good analogs. Finally, estimate JWST out ∼ 8 young compared age