Astronomers have uncovered the largest cosmic explosion ever witnessed, known as AT2021lwx. The event is more than ten times brighter than any known supernova and three times more luminous than the brightest tidal disruption event. Scientists from the University of Southampton believe that this extraordinary phenomenon may be caused by a vast cloud of gas, potentially thousands of times larger than our sun, being violently disrupted by a supermassive black hole.
The initial detection of this explosion occurred in 2020 through the efforts of the Zwicky Transient Facility (ZTF) in California and was later picked up by the Asteroid Terrestrial-impact Last Alert System (ATLAS) based in Hawaii. Just last year, astronomers had observed what was previously considered to be the brightest explosion on record – a gamma-ray burst known as GRB 221009A.
Dr. Kate Maguire, an astrophysicist at University of Southampton said "Our discovery highlights how much there still is to learn about these phenomenal events and emphasizes just how important new facilities like Vera Rubin Observatory's Legacy Survey will be for future discoveries."
The findings are published in Monthly Notices of Royal Astronomical Society indicating that AT2021lwx is likely fueled by consumption of an enormous gas cloud by a supermassive black hole approximately eight billion light-years away from Earth. It took several months after its first detection before scientists were able to calculate its distance using clues imprinted on its light.
Lead author Dr. Matt Nicholl shared his excitement about their hypothesis: “We proposed that this incredible explosion was sparked when a huge hydrogen gas cloud collided with an immense supermassive black hole around 100 million times more massive than our Sun.”
To confirm their theory, researchers plan to continue observing AT202021rwx while searching for similar transient outbursts. Given the longevity of these explosions, they may provide valuable insight into the enigmatic co-evolution of galaxies and supermassive black holes.
As new facilities like the Vera Rubin Observatory's Legacy Survey of Space and Time come online in the next few years, scientists are hopeful that they will be able to uncover even more extraordinary events like AT2021lwx and gain a deeper understanding of their origins.