First dormant stellar-mass black hole detected outside our galaxy; is at least nine times the Sun's mass

Astronomers have discovered a stellar-mass black hole in the Large Magellanic Cloud (LMC), a neighbouring galaxy, which they claim is the first 'dormant' stellar-mass black hole to be unambiguously detected outside our galaxy.

The team, nicknamed 'black hole police',found that the star that gave rise to the black hole vanished without any sign of a powerful explosion. The dormant black hole is at least nine times the mass of our Sun, and orbits a hot, blue star weighing 25 times the Sun's mass.

"For the first time, our team got together to report on a black hole discovery, instead of rejecting one. We identified a 'needle in a haystack', says study leader Tomer Shenar who started the study at KU Leuven in Belgium and is now a Marie-Curie Fellow at Amsterdam University, the Netherlands.

1/ A team of international experts, renowned for debunking several black hole discoveries, have found a stellar-mass black hole in the Large Magellanic Cloud, a neighbour galaxy. 🔗 https://t.co/pZoWcTLPtMArtist's impression: @ESO /L. Calçada pic.twitter.com/nGKBsN03bq

— ESO (@ESO) July 18, 2022

According to a post by the European Space Observatory (ESO), the black hole in VFTS 243 was found using six years of observations of the Tarantula Nebula by the Fibre Large Array Multi Element Spectrograph (FLAMES) instrument on ESO's Very Large Telescope (VLT). The team, renowned for debunking several black hole discoveries, searched nearly 1000 massive stars in the Tarantula Nebula region of LMC.

"The star that formed the black hole in VFTS 243 appears to have collapsed entirely, with no sign of a previous explosion. Evidence for this 'direct-collapse' scenario has been emerging recently, but our study arguably provides one of the most direct indications. This has enormous implications for the origin of black-hole mergers in the cosmos," explains Shenar.

The discovery is published in the journal Nature Astronomy.