Largest cosmic explosion ever spotted by astronomers
Researchers say they came across the explosion “by chance” and nothing on this scale had ever been witnessed before.
Friday 12 May 2023 04:16, UK
Artist's impression of a black hole accretion
Image:
Artist’s impression of a dust cloud being sent into a black hole
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Astronomers have uncovered the largest cosmic explosion ever witnessed – and it’s lasted more than three years.
The explosion, known as AT2021lwx, is believed to have come as a result of a vast cloud of gas – thousands of times bigger than the sun – being sent into a black hole after coming off its orbit.
Fragments of the cloud would have been swallowed up, creating a large dusty “doughnut” around the black hole.
Astronomers said such events are rare, but nothing on this scale has been witnessed before.
Dr Philip Wiseman, research fellow at the University of Southampton, who led the research, said: “We came upon this by chance, as it was flagged by our search algorithm when we were searching for a type of supernova.
“Most supernovae and tidal disruption events only last for a couple of months before fading away. For something to be bright for two plus years was immediately very unusual.”
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According to the study, the actual explosion took place nearly eight billion light years away, when the universe was around six billion years old, and is still being detected by a network of telescopes.
AT2021lwx was first detected by the Zwicky Transient Facility in California in 2020, and subsequently picked up by the Asteroid Terrestrial-impact Last Alert System (ATLAS) based in Hawaii.
But until now the scale of the explosion had not been known.
Last year, astronomers witnessed the brightest explosion on record – a gamma-ray burst known as GRB 221009A.
Although this was brighter than AT2021lwx, it lasted for just a fraction of the time, meaning the overall energy released by the AT2021lwx explosion was far greater.
Dr Wiseman added that these events could be the key to understanding how the centres of galaxies change over time.
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