UNITED KINGDOM: For the first time, a hibernating black hole nine times the mass of the Sun has been discovered outside the Milky Way, according to experts. This black hole is “the first to be unambiguously spotted outside our galaxy,” according to a researcher from the University of Sheffield, even though it is not the first candidate.
Before discovering what is now known as VFTS243, the researchers had been seeking black hole binary systems for more than two years. It is a “quite intriguing discovery” that comes after “several dormant black hole candidates have been postulated,” according to Paul Crowther, an astrophysics professor at the university.
Stellar-mass black holes form when massive stars die and collapse under their own gravity. This phenomenon leaves a black hole in orbit with a luminous companion star in a system of two stars spinning around each other.
The recently found dormant black hole has a mass at least nine times that of the Sun and orbits a bright blue star that is 25 times as massive as the Sun.
A group of international researchers have seen it in a neighbouring galaxy, and their analysis, which was published in Nature Astronomy, implies that the star that gave rise to VFTS 243 departed without leaving any trace of an associated supernova explosion.
Crowther has collaborated with Tomer Shenar from the Institute of Physics and Astronomy. They began their study at KU Leuven in Belgium and are currently a Marie-Curie fellow at Amsterdam University in the Netherlands as a member of the worldwide research team.
If a black hole does not produce significant amounts of X-ray radiation, the radiation used to discover such black holes is said to be inactive. Black dormant holes are challenging to find since they barely interact with their surroundings.
The large fibre array multi-element spectrograph instrument on the Very Large Telescope of the European Southern Observatory was used to conduct six years of studies of the Tarantula Nebula to discover VFTS 243.