According to a new study published in Nature Astronomy, researchers have constructed models that directly recreate the whole life cycle of some of the largest groupings of galaxies recorded in the distant universe 11 billion years ago. Cosmological simulations are important for figuring out how the universe came to be the way it is now, but many of them don’t match what astronomers see through telescopes.
Most are simply statistically constructed to resemble the real world. Constrained cosmological simulations, on the other hand, are intended to replicate the structures we see in the real world. However, the vast majority of extant simulations of this type have only been used for observations in our local universe, i.e., close to Earth, and have never been used for observations in the distant cosmos.
Metin Ata, a Kavli Institute for the Physics and Mathematics of the Universe Project Researcher and first author, and Project Assistant Professor Khee-Gan Lee, a Kavli Institute for the Physics and Mathematics of the Universe Project Assistant Professor, were interested in distant structures like massive galaxy protoclusters, which are ancestors of present-day galaxy clusters before they could clump under their own gravity.
They discovered that recent studies of distant protoclusters were frequently oversimplified, implying that they were carried out using simple models rather than simulations. “We wanted to try constructing a thorough simulation of the real distant cosmos to understand how structures began and terminated,” Ata explained. COSTCO was the end consequence (COnstrained Simulations of The COsmos Field).
Building the simulation, according to Lee, was similar to building a time machine. The galaxies that telescopes detect now represent a glimpse of the past because light from the distant universe is only now reaching Earth. “It’s like taking an old black-and-white photograph of your grandfather and turning it into a film of his life,” he explained. In this way, the researchers studied how clusters of galaxies emerge by taking photographs of “young” grandparent galaxies in the universe and then fast-forwarding their age. The light from the galaxies used by the researchers travelled 11 billion light-years to reach us.
“This is extremely crucial for the fate of such structures, whether they are isolated or part of a larger complex. If you don’t consider the environment, you’ll receive radically different results. Because we have a full simulation, we were able to consistently account for the big scale environment, which is why our forecast is more stable “Ata said.
Another reason the researchers conducted these simulations was to put the mainstream cosmological model, which is used to describe the physics of the universe, to the test. Researchers could uncover previously unnoticed differences in our present understanding of the cosmos by forecasting the final mass and distribution of objects in a given location.
The researchers were able to find evidence of three previously described galaxy protoclusters and disfavor one structure using their models. Furthermore, they were able to discover five additional structures that emerged regularly in their simulations.
This includes the Hyperion proto-supercluster, the largest and earliest known proto-supercluster, which has 5,000 times the mass of our Milky Way galaxy and will collapse into a huge 300-million-light-year filament, according to the researchers. Their work has already been used to other initiatives, such as studying the cosmic environment of galaxies and distant quasar absorption lines, to name a few. Their findings were published in Nature Astronomy on June 2nd.