Monday , November 29 2021

They rebuilt their family tree … Scientists reveal how our galaxy was created


Scientists are aware that galaxies can be created by merging galaxies that are smaller than themselves. But the origin of our Milky Way has been a mystery today.

Recently, a team of international astrophysicists managed to reconstruct the first complete family tree in our galaxy, the Milky Way, by studying the properties of globular star clusters orbiting artificial intelligence and the scientific study was published in the October issue of Monthly. Notes of the Royal Astronomical Society “.

Globular clusters

Globular clusters are dense clusters of millions of stars, almost the same age as the universe, and the Milky Way galaxy contains more than 150 of these clusters, many of which were previously formed within smaller galaxies to form the galaxy we live in today.

Astronomers have been speculating for decades that globular clusters could be used as “fossils” to reconstruct the early assembly history of galaxies. However, the observation made in recent years was only possible after the development of the latest cosmic models based on specific results.

In the new study, a team of international researchers led by Dr. Diederik Croisen of the Astronomy Center at ZAH University in Heidelberg and Dr. Joel Fever of Liverpool John Moores University were able to conclude the dates for the Milky Way unification. With other galaxies, and its family tree reconstructed using only globular star clusters, according to a note from Heidelberg University.

The genealogical tree of our galaxy includes ancient galaxies, including the newly discovered “Kraken” (University of Heidelberg).

Computer simulation

To achieve this, the researchers developed some advanced computer simulations to form galaxies similar to the Milky Way. Their simulations, called “electronic mosaic” (E-MOSAICS), are unique in that they include a complete model for the formation, evolution, and revolution of globular assemblies.

In the process, researchers were able to link the ages of globular clusters, chemical compositions, and orbital motions that were linked more than 10 billion years ago to the characteristics of ancient galaxies.

By applying this simulation to the set of globules in the Milky Way, these scattered galaxies were able to determine the number of stars that existed when they merged in the Milky Way.

“The main challenge in linking the properties of globular clusters to the history of host galaxy aggregation has always been,” Croissen explained. “Grouping galaxies is a very confusing process, in which the orbits of globe clusters are completely rearranged.”

To understand the galactic system we see today, the authors of the study used artificial intelligence and created an artificial neural network in the “E-MOSAICS” simulation to link the properties of the spherical mass to the date when the host galaxies merged. After testing the algorithm tens of thousands of times, they were amazed at how well it was able to reproduce. Building galaxy merger dates.

The discovery of an unknown ancestor of our galaxy

Based on the findings, the research team set out to decipher the history of fusions in the Milky Way, using globular clusters that are believed to have formed in the same ancient galaxy based on its orbital motion.

Applying the neural network to these groups of globular clusters, the researchers accurately predicted the unification times of star masses and ancestral galaxies. On the contrary, they also revealed a previously unknown collision between the Milky Way and a mysterious galaxy, called the “Kraken,” which occurred 11 billion years ago when the size of our galaxy did not exceed a quarter of its current size.

Scientists believed that the largest collision in our galaxy occurred about 9 billion years ago with the Gauze Entzelado Sausage, and the researchers say that these results led to the reconstruction of the entire first fusion tree in our galaxy.

Clash of galaxies (IC 2163) and (NGC 2207) This is how our galaxy was created billions of years ago (European Space Agency)

Throughout its history, the Milky Way has swallowed 5 galaxies with more than 100 million stars, and about 15 galaxies with at least 10 million stars, and the largest ancient galaxies collided with the Milky Way more than once between 6 and 11 billion years ago.

The authors of the study hope that their predictions will encourage future research to look for traces of these scattered galaxies, and researchers have already found 5 traces of these galaxies, and with current and upcoming telescopes it is possible to find them all, they say.

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