John A. Pack
This illustration depicts a black hole absorbing gas, dust and other cosmic material.
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Astronomers have detected the largest cosmic explosion ever seen, and it’s 10 times brighter than an exploding star or supernova.
The burst’s brightness, known as AT2021lwx, lasted three years, while most supernovae stay bright for only a few months.
This event, still detectable by telescopes, occurred nearly 8 billion light-years from Earth when the universe was about 6 billion years old. The luminosity of the explosion, when stars fall into supermassive black holes, is three times brighter than in tidal disruption events.
But what triggered such a long, massive cosmic explosion? Astronomers say a supermassive black hole has disrupted a cloud of gas or dust thousands of times larger than our Sun. The cloud may have been pulled from its orbit and flown into the black hole, the researchers said.
As the black hole swallows pieces of the hydrogen cloud, shock waves reverberate through the remnants of the cloud and into the rotating mass of material surrounding the black hole.
AT2021lwx event resigns The gamma-ray burst GRB 221009A 2022 is the brightest cosmic explosion on record. The gamma-ray burst was indeed bright, but it only lasted for a portion of AT2021lwx, which emits more energy overall.
The findings were released Thursday Monthly Notices of the Royal Astronomical Society.
Astronomers first detected the explosion in November 2020 through the Swicky Transient Facility in California, followed a few months later by the Asteroid Terrestrial-Impact Last Alert System in Hawaii. Both are tracking objects in the night sky that change rapidly in brightness, such as exploding stars, asteroids and comets.
“We discovered this by chance because it was flagged by our search algorithm when we were looking for a type of supernova,” lead study author Dr. Philip Wiseman, a research associate at the University of Southampton in England, said in a statement. “Most supernovae and tidal disruption events last only a couple of months before fading. Two years of brightness is immediately very unusual.
Follow-up observations were conducted using the space-based Neil Gehrels Swift Observatory, the New Technology Telescope in Chile, and the Gran Telescopio Canarias in La Palma, Spain.
By analyzing the different wavelengths of light used to observe the eruption, the researchers were able to determine the distance between Earth and the event.
“Once you know the distance to the object and how bright it appears to us, you can calculate the brightness of the object at its source,” Sebastian Honig, a professor at the University of Southampton, said in a statement.
The Asteroid Terrain-Impact Last Warning System has been monitoring the explosion every few nights for the past 2½ years.
The research team determined that the incredible luminous event was almost 100 times brighter than all 100 billion stars in the Milky Way galaxy.
The only celestial objects that rival AT2021lwx’s brightness are quasars, or supermassive black holes that continue to eat gas at high speeds.
“With a quasar, we see the brightness flickering up and down over time,” Mark Sullivan, a professor at the University of Southampton, said in a statement. “But looking back for more than a decade of not detecting AT2021lwx, and then suddenly it appears with the brightness of the brightest things in the universe, which is unprecedented.”
The team had initial theories while studying the luminescence of the explosion. Researchers now want to collect more data on different wavelengths of light to learn about the phenomenon’s details, including its temperature.
“At first, we thought the explosion might be the result of a passing black hole consuming a star. But our models show that the black hole must have swallowed up to 15 times our mass. “The sun should be bright for this long,” study co-author Dr. Matt Nicol is Associate Professor at Queen’s University Belfast, Northern Ireland.
“It’s very rare to encounter such a massive star, so we think a very large gas cloud is likely. Many massive black holes are surrounded by gas and dust, and we’re still trying to figure out why this particular black hole started feeding so intensely and suddenly.