A team of astronomers from the University of Bologna has found tests that a satellite galaxy of the Milky Way, known as the ‘Large Magellanic Cloud’ (LMC), merged with another galaxy at some point in its mysterious past.
In the article published this Monday, the researchers indicate that this discovery is “an observational proof that the hierarchical assembly process it has also worked in the formation of our closest satellites. “
Globular clusters
To test their hypothesis, the scientists looked at groups of billions of stars, known as ‘globular clusters’. The idea is that the core of such a globular cluster can hold out even after billions of years of pushing and pulling a galaxy. The researchers analyzed the chemical composition of 11 globular clusters collected by the Very Large Telescope and the Magellan telescopes of Chile.
Of the 11 globular clusters studied in the Large Magellanic Cloud, one turned out to have a distinctly different chemical composition, NGC 2005. This contains a few 200,000 stars and is located 750 light years from the center of the LMC.
Based on the chemical composition of NGC 2005, the researchers concluded that it must be a remnant of a small galaxy in which stars formed rather slowly, billions of years ago.
This small galaxy would have merged with the then relatively small Large Magellanic Cloud, over time, most of the small galaxy separated and most of the stars dispersed, but the center, the globular cluster NGC 2005, was left behind.
“NGC 2005 is the surviving witness to the ancient merger event that led to the dissolution of its parent galaxy in the Large Magellanic Cloud, the only case known so far that has been identified by its chemical fingerprints in the realm of dwarf galaxies” , the researchers write.
The Article it was published in the journal Nature Astronomy.
