Astronomers have discovered the closest pair of supermassive black holes to Earth ever observed. The pair is also closer to each other than any other supermassive black holes spotted together, and will one day merge into one giant black hole.
The researchers, led by Karina Voggel of the University of Strasbourg in France, made the discovery using the European Southern Observatory’s Very Large Telescope (ESO’s VLT). They determined the masses of the two objects by looking at the effect of their gravitational pull on other stars around them.
They found that the bigger black hole was around 154 million times the mass of the Sun, and the smaller one was a mere 6.3 million solar masses.
This is the first-time masses have been measured in this way for a pair of black holes and was only possible because of their proximity to Earth – around 89 million light-years away
While astronomers already suspected our galaxy hosted the pair of blackholes, it had not been confirmed until now.
“Our finding implies that there might be many more of these relics of galaxy mergers out there and they may contain many hidden massive black holes that still wait to be found,” says Voggel. “It could increase the total number of supermassive black holes known in the local universe by 30%.”
The study was published in Astronomy and Astrophysics.
Deborah Devis is a science journalist at Cosmos. She has a Bachelor of Liberal Arts and Science (Honours) in biology and philosophy from the University of Sydney, and a PhD in plant molecular genetics from the University of Adelaide.
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