AI Insight
This study uses COLIBRE cosmological simulations to track the relationship between galaxy mass and gas-phase metal content from the earliest galaxies at redshift z=15 (approximately 270 million years after the Big Bang) to present day. The simulations, which include detailed modeling of chemistry, dust, and multiphase gas physics, successfully reproduce observed patterns showing that this mass-metallicity relationship was established by cosmic dawn and remained relatively stable until z=5, with the relationship's slope becoming shallower at later times. The research identifies that supermassive black hole feedback shapes high-mass galaxies while supernova feedback controls metal enrichment in low-mass galaxies.
Why it matters
This work provides crucial constraints on how galaxies chemically evolve and enrich their environments with heavy elements over cosmic history, informing our understanding of the conditions that led to the formation of planets and life. The results offer testable predictions for current and future telescopes observing early universe galaxies and help validate physical models of galaxy formation.
Understand the Science
arXiv:2606.25995v1 Announce Type: new
Abstract: We present the evolution of the galaxy gas-phase mass-metallicity relation (MZR) from $z=15$ to $z=0$ in the COLIBRE cosmological hydrodynamical simulations. Amongst other novel features, COLIBRE follows the multiphase interstellar medium with gas allowed to cool to $sim 10,mathrm{K}$, and includes a new chemistry model in which hydrogen and helium are tracked in non-equilibrium, metals are allowed to mix and diffuse, and the chemical network is coupled to a self-consistent live dust model. Using fiducial COLIBRE runs spanning particle masses from $10^5,mathrm{M_{odot}}$ to $10^7,mathrm{M_{odot}}$ and box sizes $25 – 400,mathrm{cMpc}$, we derive the median, mass-weighted MZRs for star-forming galaxies and compare them with a comprehensive compilation of observational data and other simulations. COLIBRE reproduces the observed MZR across cosmic time, notwithstanding the systematic uncertainties in observational measurements of the gas-phase oxygen abundances. The simulations show excellent numerical convergence and uniquely probe the full stellar mass range sampled by current observations across all redshifts. We find that the MZR is already in place at cosmic dawn ($z approx 10$), and shows no evolution until $z approx 5$. The slope of the MZR becomes shallower at low redshifts. The turnover at the high-mass end is largely governed by feedback from active galactic nuclei (AGN), whereas the low-mass end of the MZR sensitively depends on the strength of feedback from core collapse supernovae. Variations in the star formation efficiency or depletion of oxygen on dust grains have a more minor impact on the MZR. We identify key physical processes that shape the MZR across cosmic time and highlight where future observations can further constrain galaxy formation models.