Astronomers can use supercomputers to simulate how galaxies have formed since the Big Bang 13.8 billion years ago until today. But there are a number of sources of error. An international research group, led by Lund University and Seoul National University, has for eight years used one hundred million computer hours to remedy these.
In the last decade, great progress has been made in computer simulations that can realistically calculate how galaxies form. These cosmological simulations are crucial to our understanding of where galaxies, stars and planets come from. However, the predictions from such models are affected by limitations in the resolution of the simulations and assumptions about a number of factors, such as exploding stars, galactic outflows and stellar motions. In order to minimize the sources of error and produce safer simulations, 160 researchers from 60 universities – led by Santi Roca-Fábrega at Lund University, Ji-hoon Kim at Seoul National University and Joel R. Primack at the University of California – have collaborated and now present the results of its first supersimulation.
– To make progress towards a theory of galaxy formation, it is crucial to compare results and codes from different simulations. We have now done this by bringing together competing code groups behind the world’s best galaxy simulators in a kind of super simulator, says Santi Roca-Fábrega, researcher in astrophysics.
Now three articles from this collaboration, the so-called CosmoRun simulations, are published in the scientific journal The Astrophysical Journal. In these, the researchers have analyzed the formation of a galaxy with the same mass as the Milky Way. The simulation is based on the same astrophysical assumptions about ultraviolet background radiation, gas cooling, heating and star formation. With the help of the new results, the researchers can determine that disk galaxies like the Milky Way have formed very early in the history of the universe, completely in line with observations from the James Webb telescope. They have also found a method so that the number of satellite galaxies – galaxies that orbit larger galaxies – is consistent with observations. In addition, the research team has revealed how the gas surrounding galaxies is the key behind realistic simulations, rather than the number and distribution of stars, which was previously standard.
– The work has been going on for the last eight years and involved running hundreds of simulations and using one hundred million hours on supercomputer facilities, says Santi Roca-Fábrega.
Now the journey continues towards further refining the simulations around galaxy formation. With each technological breakthrough, Santi Roca-Fáberga and his colleagues hope to add new pieces of the puzzle to the dizzying question of the birth and evolution of the universe and galaxies.
– This is the starting point for safer simulations of galaxy formation which in turn help us to better understand our home galaxy the Milky Way, says Santi Roca-Fábrega.
In addition to Lund University, around 60 universities and organizations have participated in the work.
The study is published as three articles in The Astrophysical Journal, here as e-print versions via ArXiv:
For more information contact:
Santi Roca-Fábrega, researcher in astrophysics
Department of Physics, Lund University
+46 70-727 59 78
santi.roca_fabrega@fysik.lu.se
Press contact:
johan.joelsson@science.lu.se
073 027 58 90
2024-02-23 05:45:00
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