Scientists create “time machine” simulations that study the life cycle of ancestral galaxy cities.
Many processes in astrophysics take a long time, which makes their evolution difficult to study. For example, a star like our sun has a lifespan of about 10 billion years, and galaxies have evolved over billions of years.
One way astrophysicists treat this is by looking at several different objects to compare them at different stages of evolution. They can also look at distant objects to look back in time effectively, due to the time it took light to travel to reach our telescopes. For example, if we look at an object 10 billion light-years away, we see it as it was 10 billion years ago.
Now, for the first time, researchers have created simulations that directly recreate the full life cycle of some of the largest galaxy collections observed in the distant universe 11 billion years ago, according to a new study published in June 2, 2022 in the magazine. Astronomy of nature.
Cosmological simulations are crucial to studying how the universe became the way it is today, but many do not usually match what astronomers observe through telescopes. Most are designed to match the real universe only in a statistical sense. Restricted cosmological simulations, on the other hand, are designed to directly reproduce the structures we actually observe in the universe. However, most existing simulations of this type have been applied to our local universe, that is, 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 researcher and lead author Metin Ata and Khee-Gan Lee, an adjunct professor, were interested in distant structures such as galaxy protocumulus clusters. massive, which are ancestors of the present. clusters of galaxies before they could cluster under their own gravity. They found that the current studies of distant protocumulus were sometimes oversimplified, that is, they were done with simple models and not with simulations.
The screenshots of the simulation show (above) the distribution of matter corresponding to the distribution of the galaxy observed in a light travel time of 11 billion years (when the Universe had only 2.76 billion d years or 20% of its current age) and (below) the distribution of matter in the same region after 11 billion light-years or corresponding to our current time. Credit: Ata et al.
“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.
Its result was COSTCO (Constrained Simulations of The Cosmos Field).
Lee said developing the simulation was a lot like building a time machine. Because the light from the distant universe only now reaches Earth, the galaxies that telescopes observe today are a snapshot of the past.
“It’s like finding an old black and white image of your grandfather and creating a video of his life,” he said.
In this regard, the researchers took snapshots of “young” grandparent galaxies from the universe and then quickly 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 most difficult thing was to consider the large-scale environment.
“This is very important for the destination of these structures, whether they are isolated or associated with a larger structure. If you do not take into account the environment, you get completely different answers. We have been able to take into account the environment in large scale consistently, because we have a complete simulation, and that’s why our prediction is more stable, “Ata said.
Another important reason why 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 final distribution of structures in a given space, researchers could reveal previously undetected discrepancies in our current understanding of the universe.
Through their simulations, the researchers were able to find evidence from three galaxy clusters already published and disfavor a structure. In addition, they were able to identify five more structures that were constantly formed in their simulations. This includes the Hyperion proto-supercluster, the largest and oldest known proto-supercluster that is 5,000 times the mass of our Milky Way galaxy, which researchers discovered would collapse into a large filament of 300 million light years.
His work is already being applied to other projects, including those to study the cosmological environment of galaxies and the absorption lines of distant quasars, to name a few.
Details of his study were published in Nature Astronomy on June 2.
Reference: Metin Ata, Khee-Gan Lee, Claudio Dalla Vecchia, Francisco-Shu Kitaura, Olga Cucciati, Brian C. Lemaux, Daichi Kashino and Thomas Müller 2. June 2022, Nature Astronomy.DOI: 10.1038 / s41550-022-01693-0