A new simulation maps the first seconds after the Big Bang, focusing on what scientists call the intergalactic medium, or the gas and dust between galaxies.
A team led by researchers from the Institute of Astrophysics of the Canary Islands (IAC) used machine learning, a type of algorithm in which a computer is trained to recognize patterns, to complete 100,000 hours of computation. The algorithm for this project is called Hydro-BAM.
This new work has allowed researchers to map phenomena such as dark matter, energized gas, neutral hydrogen and other cosmic ingredients essential to understanding the structure of our universe, the representatives of the IAC in a May 20 statement. (opens in a new tab).
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“The research also allowed the so-called ‘Lyman-alpha forests’ to be replicated with great accuracy,” they added. It is a peculiar pattern of lines in a spectrum (light signature) of galaxies and similar objects created when clouds of hydrogen gas absorb galactic light.
“These ‘virtual universes’ serve as testbeds for the study of cosmology,” the researchers added. “However, simulations are very computationally expensive, and current computing facilities only allow [us] to explore small cosmic volumes.”
Hydro-BAM is designed to include probability, machine learning and cosmology, i.e. the history of the universe. “This algorithm made it possible to obtain very precise predictions in just a few tens of seconds”, explain the researchers.
Mapping absorption lines in galactic spectra has allowed the team to know where the hydrogen gas clouds are. Location is an indicator of distance, since the universe is constantly expanding. The clouds also give clues to what is contained in the intergalactic medium of gas and dust.
“The breakthrough came when we understood that the connections between the quantities of intergalactic gas, dark matter and neutral hydrogen that we were trying to model are well organized in a hierarchical way”, Francesco Sinigaglia, doctoral student at the University of La Laguna in Spain, IAC and the University of Padua in Italy, and lead author of the research, said in the statement.
The most recent review of the research was published in March in The Astrophysical Journal, and a related study was published in the same journal in November 2021.