Slovenian Scientists Assist in Discovering Largest Stellar Black Hole in the Milky Way

Astronomers from the European Space Agency have identified a massive black hole that was once a giant star. The object, named Gaia BH3, is now considered the largest stellar black hole in our Galaxy. Among the team that made this discovery were Slovenian astrophysicists Andreja Gomboc and Tomaž Zwitter, as reported by The Slovenia Times.

The Gaia Data Processing and Analysis Consortium published details of the discovery in the journal Astronomy and Astrophysics on April 16. The lead author of the report is Pasquale Panuzzo, who works at the Paris Observatory, with co-authors Tomaž Zwitter from the University of Ljubljana Faculty of Mathematics and Physics and Andreja Gomboc from the University of Nova Gorica.

Gaia BH3 has a mass of 33 solar masses, making it the largest confirmed and studied black hole of this class. The object is located in the constellation Aquila, just 2,000 light-years from Earth, which is relatively close by cosmic standards. Similar objects have been found before, but mostly outside the Milky Way, making detailed study challenging. Therefore, not only the size of Gaia BH3 but also its location makes this discovery exceptionally valuable.

"Less than ten years ago, when we discovered black hole mergers using gravitational waves, it was unclear how these black holes form in distant galaxies and how they can have such large masses. But now we have the first example of such a massive black hole literally nearby, and since it formed from an ordinary star, we can essentially say for the first time that even more distant massive black holes have formed from ordinary stars," said Tomaž Zwitter.

Scientists note that this discovery is so important that they decided to publish details about this black hole earlier than planned to allow other astronomers to conduct observations as quickly as possible. "No one could have imagined that such a massive black hole could be right next to us, remaining undetected," said Pasquale Panuzzo, adding that such a discovery can only be made once in a scientific career.

It's worth noting that stellar black holes arise from the gravitational collapse of stars and have masses ranging from 5 to several tens of solar masses. However, there are supermassive black holes with masses ranging from hundreds of thousands to billions of solar masses, typically located at the centres of galaxies. There is currently no widely accepted theory for the formation of supermassive black holes.