2026-09-30 シカゴ大学（UChicago）
Using powerful supercomputers, scientists created an extensive simulation of what the Milky Way could have looked like long ago—a chaotic progression of hot gas cooling, condensing into stars, and exploding, over and over again. Purple indicates hot gas; white is UV radiation from stars; yellow is glowing hot oxygen atoms.Image courtesy Harley Katz/MEGATRON Collaboration
＜関連情報＞
- https://news.uchicago.edu/story/new-simulation-projects-what-milky-way-looked-cosmic-dawn
- https://astro.theoj.org/article/169643-megatron-reproducing-the-diversity-of-high-redshift-galaxy-spectra-with-cosmological-radiation-hydrodynamics-simulations
- https://arxiv.org/abs/2510.05201v2
MEGATRON：宇宙論的放射流体力学シミュレーションによる高赤方偏移銀河スペクトルの多様性の再現 MEGATRON: Reproducing the Diversity of High-Redshift Galaxy Spectra with Cosmological Radiation Hydrodynamics Simulations
Harley Katz,Martin Rey,Corentin Cadiou,Oscar Agertz,Jeremy Blaizot,Alex J. Cameron,Nicholas Choustikov,Julien Devriendt,Uliana Hauk,Gareth C. Jones,Taysun Kimm,Isaac Laseter,Sergio Martin-Alvarez,Kosei Matsumoto,Autumn Pearce,Francisco Rodríguez Montero,Joki Rosdahl,Mahsa Sanati,Aayush Saxena,Adrianne Slyz,Richard Stiskalek,Anatole Storck,Oscar Veenema,Wonjae Yee
The Open Journal of Astrophysics Published:September 30, 2026
DOI:https://doi.org/10.33232/001c.169643
Abstract
We present the MEGATRON suite of cosmological radiation hydrodynamics simulations following the formation of Milky Way-mass galaxies from the earliest cosmic epochs when Population III stars form to Cosmic Noon. The suite represents the first set of cosmological simulations that couples a vast non-equilibrium thermochemistry network of primordial species, metals, and molecules to multifrequency, on-the-fly radiation transport, allowing us to directly predict the spectral properties of early galaxies. By initializing the simulations at zero metallicity, resolving haloes well below the atomic cooling threshold, reaching parsec-scale resolution, and modeling a Milky Way-mass environment, we aim to address four key science themes: 1) Star formation at cosmic dawn, 2) Galaxy formation and the interstellar medium in the epoch of reionization, 3) The circumgalactic medium towards cosmic noon, and 4) Reionization in a local volume environment and near-field cosmology. In this introductory work, we present an overview of the physical characteristics of high-redshift MEGATRON galaxies and their environment at z>8. We present a library of >175,000 simulated galaxy spectra and demonstrate how much of the diversity of galaxy spectra seen by JWST is naturally reproduced in the context of a ΛCDM cosmology. Caveats are discussed, such as the lack of AGN in our simulations and the limitations of our adopted stellar population and chemical yield models. This project represents a step towards making more direct comparisons between simulations and observations and is particularly applicable for optimizing methods to infer galaxy properties from existing high-redshift JWST spectra and imaging data.
