London, Feb 23 : Astronomers have confirmed the existence of the heaviest known black hole in the Universe.
According to a report in New Scientist, the black hole known as IC 10 X-1, discovered in 2007, is between 24 and 33 times the Sun's mass.
The previous record holder is a black hole in the nearby galaxy M33. Called M33 X-7, it was measured to have 16 times the Sun's mass.
These stellar-mass black holes form when a massive star dies, sending its outer layers exploding outwards in a supernova and collapsing its core into a black hole.
Earlier analysis, which was based on the apparent orbit of a nearby companion star of the black hole, didn't confirm IC 10 X-1 as being the heaviest one. That's because the orbit was deduced from repeating dips in the brightness of X-rays coming from the black hole's vicinity.
Astronomers suspected the dips occurred when the companion star periodically passed in front of a disc of hot, X-ray emitting matter spiralling into the black hole, but there was no evidence to prove it.
But now, astronomers Jeffrey Silverman and Alexei Filippenko at the University of California, Berkeley, US, have confirmed the result.
Their observations suggest the black hole weighs between 23 and 33 solar masses.
Stars can be born with more than 100 times the mass of the Sun, but over time they shed some material into space. The amount they lose depends on their chemical makeup - even the biggest stars can barely produce a 16-solar-mass black hole if they are born with a composition similar to the Sun's.
"Stars low in elements heavier than hydrogen and helium, however, cast off material less efficiently and could therefore have up to 42 solar masses available to form a black hole when they die," said astrophysicist Stanford Woosley of the University of California, Santa Cruz.
As it turns out, the nearby dwarf galaxy IC 10, which hosts the black hole, contains very few "heavy" elements.