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Astronomers discover remnants of an ancient merger in the Large Magellanic Cloud

Astronomers discover remnants of an ancient merger in the Large Magellanic Cloud

The discovery confirms the suspicion that smaller galaxies are in turn made up of smaller galaxies.

We’ve known for some time that our Milky Way has grown by devouring smaller galaxies. By the way, it has been proven in recent years that in fact all large galaxies are formed by consuming smaller galaxies. Now researchers have proven that not only giants are guilty.

Large Magellanic Cloud
The researchers wanted New study Show the conjecture that smaller galaxies in turn also consist of smaller galaxies. To test this hypothesis, they studied the Large Magellanic Cloud, a neighboring galaxy to the Milky Way.

About the Magellanic Clouds
Magellanic Clouds are galaxies visible to the naked eye in the night sky. The Large Magellanic Cloud is about 160,000 light-years away and is the third closest galaxy to the Milky Way. The Small Magellanic Cloud is about 200,000 light-years away. Both galaxies are made up of hundreds of millions of stars. Until recently, astronomers believed that the Large Magellanic Cloud would continue to orbit the Milky Way for billions of years, or perhaps eventually escape the gravitational pull of our Milky Way. But recent measurements show that the Large Magellanic Cloud contains much more dark matter than previously thought. As a result, the galaxy is drawn towards the Milky Way, as it were. Several years ago, researchers demonstrated that The galaxy is on a collision course with the Milky Way.

In particular, the team looked at so-called globular clusters: large balls, made up of stars, orbiting around the centers of galaxies. This globular cluster is made up of hundreds of thousands of – often older – stars. The idea is that the core of such a globular cluster could withstand even after billions of years of galactic thrust and thrust.

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chemical composition
The researchers analyzed the chemical composition of 11 globular clusters in the Large Magellanic Cloud. They did this with the Chilean Very Large Telescope and the Magellan Telescopes. Surprisingly, of the eleven globular clusters studied, one was found to have a markedly different chemical composition: the globular cluster NGC 2005.

NGC 2005
Bolhoop NGC 2005 is located 750 light years from the center of the Large Magellanic Cloud and contains about 200,000 stars. The globular cluster contains, among other things, less zinc, copper, silicon, and calcium than the other 10 globular clusters studied.

Composite image of NGC 2005 (left) and the Large Magellanic Cloud (right). The chemical composition of stars in NGC 2005 differs from that of other stars in the Large Magellanic Cloud. It is the first evidence of a merger of dwarf galaxies outside our Milky Way. Photo: HLA / Fabian RR / ESO / VMC Survey / [CC BY-SA 3.0]

Based on the chemical composition of NGC 2005, the researchers argue that this globular cluster must be the remnant of a small galaxy in which stars formed very slowly.

small galaxy
Billions of years ago, the small galaxy would have merged with the Large Magellanic Cloud – not very big. Over time, most of the small galaxies split and most of the stars became scattered. But the center – the globular cluster NGC 2005 – was left behind.

This means that astronomers have found real remnants of an ancient merger process in the Large Magellanic Cloud. So this neighboring galaxy actually contained a smaller galaxy from a different environment, confirming the researchers’ hypothesis. Researcher David Massari, who works in Italy and the University of Groningen, is pleased. “We have now convincingly demonstrated for the first time that small galaxies near our Milky Way are in turn made up of smaller galaxies,” he concludes.