A giant black hole with a mass of 30 billion suns was located hundreds of millions of light-years from Earth, a new study has revealed. This is one of the four black holes ever observed, the researchers said in a statement. Astronomers are referring to it as an ultramassive black hole, unlike the usual galactic supermassive black holes that weigh between a few million to billion solar masses.
This is the first black hole to be discovered using a phenomenon called gravitational lensing wherein light travelling towards us from a distant galaxy appears to magnify and bend inwards, giving away the presence of a dark giant. The findings of the study were published in the journal Monthly Notices of the Royal Astronomical Society.
Supermassive black holes are found at the centre of galaxies and have an extremely strong gravitational pull that does not allow even light to escape.
James Nightingale, an astronomer at the UK's Durham University and the study's lead author, told AFP that the process was "similar to shining light through the base of a wine glass". Talking about gravitational lensing, Nightingale said it allowed astronomers to "discover black holes in the other 99 percent of galaxies that are currently inaccessible.” Currently, there are about 500 known gravitational lenses and at least one is known to be a supermassive black hole. However, "the landscape is about to dramatically change," Nightingale told the AFP.
Gravitational lensing makes it possible to study inactive black holes, something not currently possible in distant galaxies, Nightingale added in the statement. This approach could possibly help locate many more black holes.
Previous black holes of similar size were located when they give off massive amounts of light at the margins or by measuring the orbit of stars that speed up as they pass by, according to the statement by the researchers. This could be the biggest black hole ever recorded, but it was difficult to confirm because of the varying techniques and uncertainties involved, Nightingale told AFP.
For this discovery, computer simulations and images from the Hubble Space Telescope were used to confirm the findings and eliminate other possibilities, such as an over-concentration of dark matter. The huge size is also consistent with what would be expected for a black hole at the centre of its giant host galaxy, Nightingale said.
The researchers hope this is the first step towards deeper exploration of the mysteries of black holes, and that future large-scale telescopes can help study more distant black holes, their statement added.