QUB researchers spot a new type of massive cosmic explosion

7 Sep 2023

Artist's impression of a black hole destroying a nearby star. The researchers believe this is the cause of the detected cosmic explosion. Image: ESA/C Carreau

The QUB study claims this explosion is as bright as billions of suns but lasts half as long as supernovae, which suggests it is a new type of cosmic phenomenon.

Researchers at Queen’s University Belfast (QUB) claim to have spotted one of the brightest ever cosmic explosions.

The team detected an explosion that appeared to be a type of supernova, which is when a star explodes at the end of its life cycle, releasing a massive cloud of hot gas and space dust into the cosmos. But further analysis suggests this explosion is a different phenomenon entirely.

This particular cosmic explosion – named AT2022aedm – was first spotted by a network of telescopes in Hawaii, Chile and South Africa known as ATLAS. Follow-up data from observatories around the world suggest that the explosion faded and cooled down much faster than expected.

The QUB study claims this explosion is as bright as billions of suns and only lasts half as long as typical supernovae. QUB’s Dr Matt Nicholl said this explosion is “one of the brightest we’ve ever seen”.

“Usually, with a very luminous supernova, it will have faded to maybe half of its peak brightness within a month,” Nicholl said. “In the same amount of time, AT2022aedm faded to less than one per cent of its peak – it basically disappeared.”

QUB’s Dr Shubham Srivastav said that the location of the cosmic explosion is also surprising, as it took place in a massive “red galaxy” that is 2bn light years away.

“These galaxies contain billions of stars like our sun, but they shouldn’t have any stars big enough to end up as a supernova,” Srivastav said.

The discovery has opened up avenues for more research, according to Nicholl, who believes the most plausible explanation for this explosion is “a black hole colliding with a star”.

“The exquisite data set that we have obtained rules out this being another supernova,” Nicholl said. “We have named this new class of sources ‘Luminous Fast Coolers’ or LFCs. This is partly to do with how bright they are and how fast they fade and cool.”

Nicholl added that the name was also chosen as some of the researchers are “huge fans” of the Liverpool football club, adding that “it’s a nice coincidence that our LFCs seem to prefer red galaxies”.

Earlier this year, the James Webb Space Telescope managed to capture images of a massive star in its Wolf-Rayet phase, which is a brief period where stars shed their outer layers before going supernova.

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Leigh Mc Gowran is a journalist with Silicon Republic