.jpg)
Simulation of the first galaxies in the Universe.
Image Credit: Harley B. Katz, Martin P. Rey
Scientific Frontline: Extended "At a Glance" Summary: The MEGATRON Project and Cosmic Chemical Fingerprints
The Core Concept: The MEGATRON project utilizes high-resolution cosmological simulations to model the formation of the first stars and galaxies, tracking how their radiation and supernova explosions enriched the early universe with heavy chemical elements.
Key Distinction/Mechanism: Unlike simplified previous models, MEGATRON simultaneously tracks gas movement, starlight propagation, and chemical evolution at an exceptionally high resolution, providing a physical bridge between direct observations of the early universe (via the James Webb Space Telescope) and the chemical "fossil record" preserved in ancient Milky Way stars.
Origin/History: The MEGATRON project began in 2023 and is scheduled to continue until 2030, with its first substantial body of results—four studies published in the Open Journal of Astrophysics—released in September 2026.
Major Frameworks/Components:
- High-resolution cosmological simulations modeling pristine gas conditions post-Big Bang.
- Models of stellar radiation and supernova dispersal mechanisms.
- Tracking of chemical element concentration and evolution over billions of years.
- Integration of James Webb Space Telescope (JWST) observational data with stellar archaeology (the chemical analysis of ancient local stars).
Branch of Science: Astrophysics, Cosmology, Astrochemistry.
Future Application: Future iterations of the simulations, utilizing 40 million processor hours on UK national supercomputers, aim to provide even higher resolution models, allowing for more direct comparisons with emerging JWST data and large-scale stellar surveys to test competing models of early star formation.
Why It Matters: This research is critical for answering one of astronomy's fundamental questions: the origin and distribution of the heavy elements (such as carbon, oxygen, and iron) necessary for the formation of planets and the emergence of life.
This image shows what our galaxy could have looked like 12 billion years ago. Though young, the galaxy could already have formed a rotating disk like we see today, with a significant amount of heavy elements and dust. The bands of light to the north and south are remnants from a gigantic collision of two galaxies, which left a trail of stars.
Image Credit: Courtesy Harley Katz/MEGATRON Collaboration
Researchers have used some of the most detailed simulations yet of the early universe to investigate how the first stars and galaxies formed.
Led by researchers at the University of Bath, alongside collaborators at the University of Chicago in the United States and the Institut d’Astrophysique de Paris in France, the MEGATRON project uses advanced simulations to explore how the first stars and galaxies lit up the previously dark cosmos and enriched it with the chemical elements that would later become the building blocks of everything around us.
Published today in the Open Journal of Astrophysics, four studies from the MEGATRON project combine cutting-edge cosmological simulations with sophisticated models of radiation, chemistry, and galaxy formation. Together, these constitute the collaboration's first substantial body of published results, with further papers expected to follow.
The findings from the study of the first stars show that accurately capturing the interplay between starlight, gas, and newly forged elements is essential for connecting two previously separate views of the early universe: observations of young galaxies by the James Webb Space Telescope (JWST) and the chemical clues preserved in ancient stars in and around the Milky Way—the galaxy that contains our solar system.
JWST provides a direct view of galaxies in the infant universe, while ancient stars act as a fossil record of cosmic history. By studying the chemical fingerprints of these ancient stars, astronomers can reconstruct the properties of the first stars and trace how they enriched the cosmos with the first chemical elements.
The simulations follow the evolution of a young galaxy that will eventually grow into a system similar in mass to the Milky Way. Using advanced computer models that simultaneously track the movement of gas, the propagation of starlight, and the evolution of chemical concentrations, the team investigated how stars shape the gas in and around galaxies over billions of years.
The study suggests that simplified models may underestimate the influence of stellar radiation and complex chemical processes on the gas surrounding galaxies. By modeling these effects at exceptionally high resolution, the team resolved structures in the gas that are not captured by simpler models, helping to improve predictions for current and future astronomical observations.
A Direct Glimpse of the Infant Cosmos
Dr. Martin Rey, from the Department of Physics at the University of Bath and a lead contributor to the MEGATRON collaboration, said, "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."
The simulations begin with pristine gas containing no heavy elements, mirroring conditions shortly after the Big Bang. They then follow the birth of the first stars, the radiation they emit, the supernova explosions that mark their deaths, and the dispersal of newly forged elements into subsequent generations of stars and galaxies.
Understanding this process is central to one of astronomy's most fundamental questions: where the elements that make up today's universe came from.
Dr. Rey said, "The elements that make our world and life possible—carbon, oxygen, iron, and many others—were forged by stars. To understand where those elements came from, we need to understand how the first stars formed and enriched their surroundings. MEGATRON allows us to test these ideas directly by comparing detailed simulations with observations from JWST and the chemical fingerprints preserved in ancient stars."
Looking ahead, the team plans to use MEGATRON to strengthen links between theory and emerging observational data. As JWST continues to transform our understanding of the earliest galaxies, large-scale stellar surveys will provide increasingly detailed information about ancient stars in and around the Milky Way.
Dr. Rey and his colleagues at Bath are already developing the next generation of simulations. The project has been awarded 40 million processor hours on the United Kingdom's national supercomputers, equivalent to running 5 million laptops in parallel for a year. These resources will enable simulations with higher resolution and more complete physical models, allowing even more direct comparisons with JWST observations and the chemical fossil record preserved in ancient stars.
"MEGATRON provides a common physical framework for interpreting two of astronomy's most exciting new datasets: JWST's view of the earliest galaxies and the stellar fossil record," said Dr. Rey. "Together, these complementary observations allow us to test competing models of the first stars in ways that weren't previously possible."
The MEGATRON project started in 2023 and is scheduled to run until 2030.
Funding: NASA, European Research Council, National Research Foundation of Korea, Yonsei Fellowship, Science and Technology Facilities Council, Kavli Institute for Cosmological Physics, Flemish Fund for Scientific Research, Swiss National Foundation, Knut and Alice Wallenberg Foundation, UKRI Frontier Research, Swedish Research Council, Swedish National Space Agency, LMK Foundation, Oriel College Research Fund.
Published in journal: The Open Journal of Astrophysics
Title: MEGATRON: how the first stars can create an iron metallicity plateau in the smallest dwarf galaxies
Authors: Martin Rey, Harley Katz, Corentin Cadiou, Mahsa Sanati, Oscar Agertz, Jeremy Blaizot, Alex J. Cameron, Nicholas Choustikov, Julien Devriendt, Uliana Hauk, Alexander P. Ji, Gareth C. Jones, Taysun Kimm, Isaac Laseter, Sergio Martin-Alvarez, Kosei Matsumoto, Autumn Pearce, Yves Revaz, Francisco Rodriguez Montero, Joki Rosdahl, Aayush Saxena, Adrianne Slyz, Richard Stiskalek, Anatole Storck, Oscar Veenema, and Wonjae Yee
Source/Credit: University of Bath
Edited by: Scientific Frontline
Reference Number: asph093026_01
