Astrophysics is complicated because many processes take a long time. This makes it difficult to study their evolution. A star such as our sun can live for about 10 billion years, while galaxies are constantly evolving over billions of years.
Astrophysicists can help with this by comparing different objects at different stages in their evolution. Because of how long it took for light to reach our telescopes, they can also see distant objects to peer back in time. If we look at an object ten billion light-years away, we see it as it was ten years ago.
Researchers have now produced simulations that accurately recreate the life cycle of the most massive collections of galaxies found in the universe before eleven billion years. This is recent study published in Journal Nature Astronomy on June 2, 2022.
Cosmological simulations can be very helpful in understanding the origins of the universe. However, many of them don’t match the view of astronomers using their telescope. Many simulations are only statistically comparable to the actual universe. The constrained cosmological simulations are planned to reproduce the structures we see in the universe. Most simulations of this nature have simulated the local universe (near-Earth), but not for distant observations.
Metin Ata, Kavli Institute of the Mathematics and Physics of the Universe Project researcher, and Professor Khee Gan Lee (Project Assistant) were both interested in distant structures, such as large galaxy protoclusters. These were the ancestors to the current-day clusters, and may have clumped under their gravitation. Studies on distant protoclusters have been simplified in many cases, which means that they are based on simple simulations and not complex models.
Ata stated, “We wanted to develop a complete simulation in the distant universe to see how structures began & ended.”
They came up with COSTCO (COnstrained Simulations of The COsmos Field).
Lee said that the process of creating the simulation is a kind of building a time machine. The galaxies telescope today only see a snapshot of the distant universe, as light from it is still reaching Earth.
He said, “It’s almost like finding an old black and white photograph of your grandfather. Then you make a video about his life.”
In this way, researchers took photos of “young” grandparent galaxies and fast-forward their age to see how clusters of galaxies might form.
What was most challenging was taking the large-scale environment into account.
This is crucial for the fate of these structures, regardless of whether they are separate or linked to a larger structure. You will get totally different results if you don’t consider the environment. Ata stated that we were able to take into account the large-scale environment because we had a full simulation. This is why our prediction was more stable.”
Researchers also created these simulations to test the standard model for cosmology that describes the physics and dynamics of the universe. Researchers could uncover previously undiscovered discrepancies in the current universe understanding by forecasting the distribution of structures or final mass in space.
The researchers found proof of three previously available galaxy protoclusters using their simulations. They also discovered disfavor one structure. They were also able to identify five additional structures that formed consistently in their simulations. The Hyperion proto-supercluster is the largest proto-supercluster that exists today. It has a mass of 5000 times our Milky Way galaxy. Researchers discovered it would eventually collapse into a large 300,000,000 light-year filament.
Their research is being used in other projects, with the study of the cosmological environment of galaxies and absorption lines for distant quasars.