MEGATRON is a good guy!?! Well, at least to cosmologists who are using this simulation to transform (sorry, couldn't resist) our understanding of the universe's first stars. Of course, in this case Megatron isn't the diabolical leader of the Decepticons who killed Optimus Prime in the Transformers franchise, but the most detailed simulation to date of the early universe.
Beginning in 2023 and set to run until 2030, MEGATRON uses James Webb Space Telescope (JWST) data to combine cutting-edge cosmological simulations with sophisticated models of radiation, chemistry, and galaxy formation. This allows researchers to investigate how the first galaxies and the first stars, known as Population III (POP III) stars, lit the shadows of the cosmic dark ages.
This is an important quest; POP III stars were primarily composed of hydrogen and helium, the lightest elements, and all that was available in the universe's infancy. However, during their lives, POP III stars forged heavier elements, which astronomers call metals. Upon their supernova deaths, POP III stars distributed elements like nitrogen, carbon, and oxygen to become the building blocks of the next generation of stars, their planets, and eventually life itself, be it here on Earth or anywhere else it exists in the cosmos.
"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," Martin Rey from the Department of Physics at the University of Bath said in a statement. "MEGATRON allows us to test these ideas directly by comparing detailed simulations with observations from JWST and the chemical fingerprints preserved in ancient stars."
This new research represents the first major finding from MEGATRON. So what did it find?
MEGATRON saves the day!?!
The first MEGATRON results demonstrate the importance of the interplay between starlight, gas, and newly forged elements in connecting astronomical data of galaxies in the early universe provided by the JWST and chemical fingerprints found within ancient stars in our galaxy, the Milky Way.
"The JWST 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," Rey explained. "MEGATRON provides a physical bridge between the two."
This unification could reconstruct the properties of POP III stars, in turn revealing how they enriched their surroundings with metals.
MEGATRON did this by simulating the evolution of a young galaxy that had the potential to grow into a system similar in mass to the Milky Way, beginning with pristine unspoiled hydrogen and helium gas. The simulation tracked the motion of gas, the passage of starlight, and the change in chemical concentrations, thus revealing how stars shape the gas in and around galaxies over billions of years.
The findings imply that some cosmological models may underestimate just how important the radiation emitted by stars and the chemical changes in gas around galaxies are to cosmic evolution.
With high-resolution reconstructions of these factors, MEGATRON recreated structures in the gas that fail to manifest in simpler models. This could improve predictions for current and future astronomical observations.
The team will now continue to use MEGATRON to forge even stronger links between astronomical observations and theory. This will become even more vital as the JWST continues to transform our understanding of the earliest galaxies and as large-scale astronomical surveys provide increasingly detailed information about ancient stars in our cosmic backyard.
"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," Rey concluded. "Together, these complementary observations allow us to test competing models of the first stars in ways that weren't previously possible."
The team's research was published across four papers in the Open Journal of Astrophysics, with more to come.
