MEGATRON simulations show simpler galactic models underestimate stellar radiation

Between 100 and 400 million years after the Big Bang, the first stars and galaxies formed in a universe dominated by hydrogen and helium. Even with the advanced optics of the Hubble Space Telescope and the James Webb Space Telescope, astronomers still cannot directly resolve these ancient stars when viewing the early universe. To bridge this gap, an international research team developed the MEGATRON project, a cosmological simulation suite designed to recreate the infant cosmos.

The MEGATRON Simulation Project

The MEGATRON project began in 2023 and is scheduled to run until 2030, combining advanced cosmological simulations with models of radiation, chemistry, and galaxy formation. The simulation suite tracks the movement of gas, the propagation of starlight, and the evolution of chemical concentrations over billions of years. Researchers used these models to follow a young galaxy that eventually grew to a mass comparable to the Milky Way. The simulations start with pristine gas containing no heavy elements, following the birth of Population III stars, their intense radiation, and their supernova explosions.

Connecting JWST Observations to Ancient Milky Way Stars

The project explores how the earliest stars illuminated a dark universe and produced the chemical elements essential for planets and life. The first results from the project demonstrate that capturing the interplay between starlight, gas, and newly forged elements is essential.

The James Webb Space Telescope gives us a direct glimpse of the infant cosmos, while stellar archaeology allows us to study the relics of those earliest times in our own Galactic neighborhood. MEGATRON provides a physical bridge between the two.

Dr. Martin Rey

As Dr. Martin Rey from the University of Bath explained, MEGATRON provides a common physical framework for interpreting JWST observations and the stellar fossil record.

New Research Shows Simpler Galactic Models Underestimate Stellar Radiation

The findings from the initial phase were published across four papers in the Open Journal of Astrophysics by researchers from institutions including the University of Bath, the Kavli Institute for Cosmological Physics, and the Institut d’Astrophysique de Paris. The results indicate that simpler models of galactic evolution previously underestimated how stellar radiation and complex chemical processes influence gas in the intergalactic medium.