2025/10/22 by Samir Kušmić, Kusmic, Samir, Kristian Finlator +5
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.2510.20021
openalex publication_date 2025/10/22 · openalex created_date 2025/10/25 · openalex updated_date 2026/07/28
We compare the Technicolor Dawn cosmological simulations with recent observations of galactic nebular line emission during the Epoch of Reionization, providing stringent tests of the predicted ionization and metal enrichment levels. We validate the simulated population with the UVLF and MUV-M_* relation and see that the simulated results are consistent with observations at lower masses. We extract local gas volumetric grids of density and mass-weighted metallicity, then we use Cloudy to produce synthetic emission spectra of \speciesHii regions. The mass-metallicity relation does not evolve, which is also consistent with observations. The predicted oxygen abundance exceeds observational inferences by about 0.5 dex, suggesting either overly efficient enrichment or weak feedback. However, applying the O32 diagnostic directly to our synthetic spectra shows an offset of 1 dex from the correct outputted gas-phase metallicity. This suggests that O32 is biased high at a level that is more than sufficient to account for the simulation-observation offset. The simulated galaxies' line diagnostics show mostly weaker [\speciesOiii] lines and lower diagnostic values of O3 and Ne3O2 compared to observations. This suggests higher ionization parameters within the simulated galactic population in general.