
First Dormant Black Hole Found Outside the Milky Way (theguardian.com) 35
A dormant black hole nine times the mass of the Sun has been found outside the Milky Way for the first time, in what researchers have called a "very exciting discovery." The Guardian reports: Though it is not the first contender, a researcher from the University of Sheffield says this black hole is "the first to be unambiguously detected outside our galaxy." The researchers had been looking for black hole binary systems for more than two years before finding what has become known as VFTS243. Stellar-mass black holes are formed when massive stars reach the end of their lives and collapse under their own gravity. In a system of two stars revolving around each other, this process leaves behind a black hole in orbit with a luminous companion star.
The newly discovered dormant black hole is at least nine times the mass of the Earth's Sun, and orbits a hot blue star weighing 25 times as much as the Sun. It has been observed in a neighboring galaxy by a team of international scientists; their study -- published in Nature Astronomy -- suggests that the star that gave rise to VFTS243 vanished without any sign of an associated supernova explosion. Confirming the likelihood of what he termed a "direct-collapse scenario," Paul Crowther, professor of astrophysics at the University of Sheffield, believes this has "enormous implications for the origin of black hole mergers in the cosmos."
The newly discovered dormant black hole is at least nine times the mass of the Earth's Sun, and orbits a hot blue star weighing 25 times as much as the Sun. It has been observed in a neighboring galaxy by a team of international scientists; their study -- published in Nature Astronomy -- suggests that the star that gave rise to VFTS243 vanished without any sign of an associated supernova explosion. Confirming the likelihood of what he termed a "direct-collapse scenario," Paul Crowther, professor of astrophysics at the University of Sheffield, believes this has "enormous implications for the origin of black hole mergers in the cosmos."