Researchers have discovered a dormant black hole outside the Milky Way.
The stellar-mass black hole was observed in a nearby galaxy by a team of international scientists.
The newly discovered black hole is at least nine times the mass of the sun and orbits a hot blue star weighing 25 times the mass of the sun.
The star that gave birth to the black hole disappeared without any signs of an associated supernova explosion, the study suggests.
Stellar-mass black holes form when massive stars reach the end of their lives and collapse under their own gravity.
In a system of two stars orbiting each other, this process leaves behind an orbiting black hole with a bright companion star.
This black is considered dormant if it does not emit high levels of X-radiation, which is how these black holes are usually detected.
Dormant black holes are difficult to spot because they interact little with their environment.
The researchers had been searching for binary black hole systems for more than two years and are particularly excited about the discovery, known as VFTS243.
Paul Crowther, Professor of Astrophysics at the University of Sheffield, said: “This is a very exciting discovery.
“Although a number of dormant black hole candidates have been proposed, this is the first to be unambiguously detected outside our galaxy.”
As part of the research team, Professor Crowther worked with Tomer Shenar of the Institute of Physics and Astronomy, who started the study at KU Leuven in Belgium and is now a Marie Curie Fellow at the University of Amsterdam in the Netherlands.
Dr Shenar said: “We have identified a needle in a haystack.
“The star that formed the black hole in VFTS 243 appears to have collapsed entirely, with no signs of a previous explosion.
“Evidence for this direct collapse scenario has emerged recently, but our study provides arguably one of the most direct indications.
“This has huge implications for the origin of black hole mergers in the cosmos.”
The black hole in VFTS 243 was found using six years of observations of the Tarantula Nebula by the Fiber Large Array Multi Element Spectrograph (Flames) instrument on the European Southern Observatory’s Very Large Telescope.
The study is published in Nature Astronomy.