Black hole guards’ find a dormant Black hole outside our galaxy

A team of international experts, renowned for having debunked several black hole discoveries, identified a stellar-mass black hole in the Large Magellanic Cloud, a galaxy near the Milky Way. The discovery is now published in an article on Nature Astronomy, which includes the participation of Mark Gieles, from the Faculty of Physics, the Institute of Cosmos Sciences of the UB (ICCUB) and the Institute of Space Studies of Catalonia (IEEC).

“For the first time, our team got together to report on a black hole discovery instead of rejecting one”, notes the director of the study, Tomer Shenar. The team found that the star that gave rise to the black hole vanished without any sign of any powerful explosion. This finding has been possible thanks to six years of observations obtained with the Very Large Telescope (VLT) of the European Southern Observatory (ESO). The study, carried out by nearly forty international experts, includes the participation of members of the Institute of Astrophysics of the Canary Islands (IAC) and the University of La Laguna (ULL).

The black hole is dormant if it does not emit high levels of X-rays —the way in which these black holes are detected. The found black hole is at least nine times the mass of our Sun, and it orbits a hot blue star which weighs twenty-five times the mass of the Sun.

Dormant black holes are especially hard to detect, since they do not interact much with their surroundings. “For more than two years now, we have been looking for such black hole binary systems”, notes the co-author of the study, Julia Bodensteiner, researcher at the European Southern Observatory (ESO) in Germany. “I was very excited when I heard about VFTS 243 —she adds— which in my opinion is the most convincing candidate reported to date”.

To find the VFTS 243, the collaboration analysed about 1,000 massive stars in the Tarantula Nebula region of the Large Magellanic Cloud to find those that could have black holes as companions. Identifying these companions as black holes is difficult since there are many alternative options.

The findings allow the team to have a unique view into the processes that accompany the formation of black holes.

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