How Galaxies 'Simmered' Metals in the Cosmic Noon Era ⚡ экспресс
Using a sample of 34 galaxies at z~2.3 from the AURORA survey (JWST/NIRSpec), direct electron temperature measurements via [OIII]4363 and [OII]7320,7331 lines allowed, for the first time, application of the two-zone method and extension of the metallicity range to 7.68–8.65 dex, along with masses (10^8–10^{10.4} M☉) and star formation rates (1–100 M☉/yr). The MZR is characterized by a slope of 0.27±0.04 and normalization of 12+log(O/H)=8.44±0.04 at 10^{10} M☉, with an internal scatter of 0.10 dex. Comparison with six simulations shows that none reproduce the evolution of the normalization between z~0 and z~2, pointing to an incomplete description of enrichment and feedback during the cosmic noon. Accounting for observational bias (all objects lie on the main sequence) raises O/H by ~0.1 dex at a mass of 10^{9.3} M☉, improving agreement with TNG. The z~2.3 sample agrees with the local FMR to within 0.1 dex, confirming that smooth secular regulation mechanisms were already at work at cosmic noon.
Galaxies are like giant kitchens where, in stellar cores, light atoms are fused into heavy ones — much like flour and water becoming bread. When a star dies, it spills its accumulated riches into the interstellar gas, seasoning it with 'spices': oxygen, carbon, iron. The James Webb Telescope caught the faint glow of heated oxygen in 34 galaxies shining 3 billion years after the Big Bang. By measuring the brightness of this light, like gauging a flame's temperature, astronomers calculated the oxygen abundance — breaking light into its colors works more precisely than a kitchen thermometer here.
It turned out: the heavier the galaxy, the more oxygen it holds — a relationship nearly identical to that of today's nearby galaxies. But computer simulations of the universe's evolution couldn't reproduce this consistency. Back in the era of cosmic expansion 10 billion years ago, stars were born much faster, yet the recipe for metal enrichment never wavered — as if a chef cooking ten times faster never missed a gram of seasoning.
🎯 The oxygen in our breath was once hurled out by an exploding massive star — we inhale the ashes of supernovae.