Global Courant 2023-05-12 09:12:02
The explosion – AT2021lwx – is a fireball 100 times the size of our solar system and 10 times brighter than a supernova.
Astronomers have identified the largest cosmic explosion ever observed, a fireball 100 times the size of our solar system that suddenly started igniting in the distant universe more than three years ago.
While the astronomers offered on Friday what they believe is the most likely explanation for the explosion, they stressed that more research was needed to understand the puzzling phenomenon.
The explosion, known as AT2021lwx, currently lasts more than three years, compared to most supernovae that are visibly bright for only a few months, according to a study published in Monthly Notices of the Royal Astronomical Society.
Led by the University of Southampton, the astronomers believe the explosion is the result of a massive cloud of gas, possibly thousands of times larger than our sun, that has been violently disrupted by a supermassive black hole.
According to the study, the explosion occurred nearly 8 billion light-years away, when the universe was about 6 billion years old and is still being detected by a network of telescopes.
Such events are very rare and nothing on this scale has been seen before, the researchers say.
Last year, astronomers witnessed the brightest explosion on record — a gamma-ray burst known as GRB 221009A, nicknamed BOAT — for Brightest Of All Time.
Although BOAT was brighter than AT2021lwx, it only lasted a fraction of the time, meaning that the total energy released by the AT2021lwx explosion was much greater.
AT2021lwx has earned the nickname “Scary Barbie” from researchers for its “terrifying energy”.
According to Danny Milisavljevic, an assistant professor of physics and astronomy at Purdue University, AT2021lwx was first assigned a random alphanumeric name when it was discovered: ZTF20abrbeie. The nickname “Scary Barbie” came from the alphanumeric designation “abrbeie” and “scary” because of his strength.
We first thought of AT2021lwx aka ZTF20abrbeie aka #ScaryBarbie was a superluminous supernova of a massive star. But there were no theoretical models that could explain the terrifying energy production that continues to this day. A supermassive black hole seems the only solution. pic.twitter.com/GldfFWltJc
— Danny Milisavljevic (@astro_dan_mil) April 26, 2023
AT2021lwx was first detected in 2020 by the Zwicky Transient Facility in California and then picked up by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Hawaii.
But until now, the magnitude of the explosion was unknown.
Philip Wiseman, a research fellow at the University of Southampton, who led the study, said: “Most supernovae and tidal disturbances only last a few months before fading. For something to be bright for two years was immediately very unusual.
It wasn’t until astronomers, including Wiseman, looked at it through more powerful telescopes that they realized what they had on their hands. By analyzing different wavelengths of light, they found out that the explosion was about 8 billion light-years away. That’s well beyond most other new flashes of light in the sky, meaning the explosion behind it must be much bigger.
It’s estimated to be about 2 trillion times brighter than the sun, Wiseman said.
Astronomers have investigated several possible explanations. One is that AT2021lwx is an exploding star – but the flash is 10 times brighter than any previously observed “supernova”.
Another possibility is what’s called a tidal disturbance, when a star is ripped apart as it’s sucked into a supermassive black hole. But AT2021lwx is still three times brighter than those events, and Wiseman said their research didn’t point in this direction.
The only comparable bright cosmic event is a quasar, which occurs when supermassive black holes swallow massive amounts of gas at the center of galaxies. But they tend to flicker in brightness, Wiseman said, as AT2021lwx suddenly started flaring out of nowhere three years ago and is still flaring up.
“We’ve never seen this thing before — it just came out of nowhere,” said Wiseman.
Now that astronomers know what to look for, they scan the sky to see if other similar explosions have been missed.
