For the first time, researchers have created simulations that directly recreate the full life cycle of some of the largest collections of galaxies observed in the distant universe 11 billion years ago, a new study reports. natural astronomy.
Cosmological simulations are crucial for studying how the universe got into the shape it is today, but many don’t typically match what astronomers observe through telescopes. Most are designed to match the real universe only in a statistical sense. Constrained cosmological simulations, on the other hand, are designed to directly reproduce the structures we actually observe in the universe. However, most of the existing simulations of this type have been applied to our local universe, that is to say near the Earth, but never for observations of the distant universe.
A team of researchers, led by Kavli Institute for the Physics and Mathematics of the Universe Project Researcher and first author Metin Ata and Project Assistant Professor Khee-Gan Lee, looked at distant structures such as massive galaxy protoclusters. , which are the ancestors of the current one. clusters of galaxies before they can clump together under their own gravity. They found that current studies of remote protoclusters were sometimes oversimplified, meaning they were done with simple models and not simulations.
“We wanted to try to develop a complete simulation of the real distant universe to see how the structures started and how they ended,” Ata said.
Their result was COSTCO (COnstrained Simulations of The COsmos Field).
Lee said developing the simulation was a lot like building a time machine. Because light from the distant universe is only reaching Earth now, the galaxies that telescopes observe today are a snapshot of the past.
“It’s like finding an old black and white photo of your grandfather and creating a video of his life,” he said.
In this sense, the researchers took snapshots of “young” grandparent galaxies in the universe, then rapidly advanced their age to study how galaxy clusters would form.
The light from the galaxies used by the researchers traveled a distance of 11 billion light-years to reach us.
The hardest part was taking into account the large-scale environment.
“It is something very important for the fate of these structures whether they are isolated or associated with a larger structure. If you ignore the environment, you get completely different answers. We were able to take the large scale of the environment into account consistently, because we have a full simulation, and that’s why our prediction is more stable,” Ata said.
Another important reason the researchers created these simulations was to test the Standard Model of Cosmology, which is used to describe the physics of the universe. By predicting the final mass and distribution of structures in a given space, researchers could unveil previously undetected discrepancies in our current understanding of the universe.
Using their simulations, the researchers were able to find evidence of three previously published galaxy protoclusters and disfavor one structure. In addition to this, they were able to identify five other structures that regularly formed in their simulations. This includes the Hyperion proto-supercluster, the largest and oldest proto-supercluster known today, which is 5,000 times the mass of our Milky Way galaxy, which researchers have found will collapse into a large filament of 300 million light years.
Their work is already being applied to other projects, including those studying the cosmological environment of galaxies and the absorption lines of distant quasars to name a few.
Details of their study have been published in natural astronomy June 2.
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