It’s a dog-eat-dog universe. Two weeks ago, on May 3, astronomers announced that they had observed a star in the process of swallowing one of its own planets. Two days ago, another group described Black holes tear apart stars and consume them In a process called tidal disruption event or TDE
Now an international team of astronomers reports that it has observed one of the most violent and energetic acts of cosmic cannibalism ever seen, the largest explosion ever seen in the history of the universe. Eight billion light-years from Earth, in the darkness beyond the Vulpecula galaxy, a black hole a billion times the size of the Sun appears to be collapsing into a giant cloud of gas. A study of the event It appeared Friday in the Monthly Notices of the Royal Astronomical Society.
On April 13, 2021, the Zwicky Transient Facility, a small telescope looking for exploding stars or supernovae, spotted a bright flash that didn’t match expectations. Most supernovae fade after a few weeks; Called AT2021lwx, it’s been going — and has been blowing up for three years now.
In fact, the explosion was first detected a year ago by the Asteroid Terrestrial-Impact Last Alert System, or Atlas, a network of robotic telescopes in Hawaii, South Africa and Chile. That was the real beginning of the disaster; As it continued, a global network of telescopes and satellites tracked it and measured its emissions across the electromagnetic spectrum, from high-energy X-rays to the infrared.
“Most supernova and tidal disruption events last only a few months before fading,” said Philip Wiseman, an astrophysicist at the University of Southampton and lead author of the new paper. “Being bright for two years is immediately very unusual.”
What was going on? “At first we thought the burst might be the result of a black hole consuming a passing star,” said Matt Nicholl of Queen’s University Belfast, who helped analyze the ongoing burst. “But our models show that this black hole would have to swallow up to 15 times the mass of our Sun to stay bright for this long.”
Another idea is that it exploded from a quasar—a burst of energy from the edge of a supermassive black hole at the heart of a galaxy. But there is no record of previous quasar activity at the site, nor any indication of a galaxy.
Among many unlikely explanations, Dr. Weissman and his colleagues concluded that a black hole the size of a billion suns was having a long feast on a giant gas cloud. They have encouraged colleagues to look for similar cases.
“AT2021lwx is an unusual event that does not fit into any common transient class,” Dr. Wiseman said in an email. “It’s one of the most luminous transients ever discovered,” he said, with a total radiation energy equivalent to 100 supernovae.
Jolt for jolt, it would put it in the company of colliding black holes. “The energy of colliding black holes is intense luminescence in gravitational waves — 10 billion times more ‘powerful’ than this explosion,” Dr. Weissman wrote. “But that power only lasts for 20 milliseconds,” the burst said, lasting for years.
