A new detection method used to reveal the black hole could pave the way for more discoveries, and help unlock the mysteries of how the objects form and evolve
Spotting a black hole in the depths of outer space is no small feat, but astronomers are hoping that a new technique could make discoveries easier, after it helped uncover a black hole lurking just outside our galaxy for the first time.
The black hole in question was located by the European Southern Observatory’s Very Large Telescope (VLT), which was used to study how its gravity influenced the movement of the objects that surrounded it. In this case, astronomers noticed disruption in the movements of a star about five times the sun’s mass, signalling the small black hole it was orbiting.
“When (smaller black holes) form a system with a star, they will affect its motion in a subtle but detectable way, so we can find them with sophisticated instruments,” explains the University of Göttingen’s Stefan Dreizler in a statement.
The black hole itself is said to be around 11 times the mass of the sun, and is located in a star cluster named NGC 1850, which inhabits the Large Magellanic Cloud (neighbouring the Milky Way at about 160,000 light-years away from Earth). Another notable aspect of the discovery is the age of the star cluster, which at a mere 100 million years old — making it an infant by celestial standards — is the youngest cluster known to contain a black hole.
“Similar to Sherlock Holmes tracking down a criminal gang from their missteps, we are looking at every single star in this cluster with a magnifying glass in one hand,” says Sara Saracino, an astrophysicist at Liverpool John Moores University, on the monitoring of NGC 1850. Researchers are trying, Saracino adds, “to find some evidence for the presence of black holes but without seeing them directly”.
This black hole is the first to be found beyond our galaxy using this technique, but it’s likely that there are many more discoveries just waiting to be made, which will help shed light on how the mysterious space objects form and evolve. “The result shown here represents just one of the wanted criminals,” Saracino continues. “But when you have found one, you are well on your way to discovering many others, in different clusters.”
Last year, a mysterious space cloud with a “heartbeat” was also found to be influenced by a neighbouring black hole, “beating” along to the same rhythm. “A cloud beating in gamma rays with the same precession period of a central black hole is very uncommon,” research leader, Dr Jian Li, told Dazed at the time. “It’s the first time we’ve detected it.”
The new research from the European Southern Observatory will be published in the Monthly Notices of the Royal Astronomical Society.