Scientists make ‘time machine’ simulations that study the life cycle of ‘cities’ in the ancestral galaxy

For the first time, scientists 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 to studying how the universe came to be in the form it is today, but many typically do not correspond to what astronomers observe through telescopes. Most are designed to match the real universe only in a statistical sense. Limited 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 used for our local universe, that is, near Earth, but never for observations of the distant universe.

A team of researchers, led by the Kavli Institute for Physics and Mathematics of the Universe Project Researcher and first author Metin Ata and project assistant Khee-Gan Lee, looked at distant structures such as massive galaxy protoclusters. , who are the ancestors of the present. galaxy clusters before they can clump together under their own gravity. They found that current studies of remote protocluses were sometimes oversimplified, meaning they were performed 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 the development of the simulation was a lot like building a time machine. Because light from the distant universe only reaches 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 making a video of his life,” he said.

In this sense, scientists took snapshots of “young” grandparent galaxies in the universe and then rapidly developed their age to study how galaxy clusters would form.

The light from the galaxies used by the scientists traveled a distance of 11 billion light-years to reach us.

The most difficult thing was to take into account the large environment.

“It is something very important for the fate of these structures, whether they are isolated or connected to 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, which is why our prediction is more stable, ”said Ata.

Another important reason why scientists made these simulations was to test the standard model of cosmology, which is used to describe the physics of the universe. By predicting the finite mass and distribution of structures in a given space, scientists were able to reveal previously undiscovered discrepancies in our current understanding of the universe.

Using their simulations, the scientists were able to find evidence for three previously published galaxy protoclusters and reject a structure. In addition to this, they were able to identify five other structures that were regularly formed in their simulations. This includes the Hyperion proto-superhob, the largest and oldest proto-superhob known today, which is 5,000 times the mass of our Milky Way galaxy, which scientists have found will collapse into a large filament of 300 million light-years.

Their work is already being used for other projects, including those studying the cosmological environment of galaxies and the absorption lines for distant quasars to name a few.

Details of their study were published in natural astronomy June 2.


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