Space scientists from NASA revealed that the gamma-ray explosion recorded last year in October was the brightest of all time (BOAT). The source was a gamma-ray burst (GRB), the most powerful class of explosions in the universe. The event occurred two billion light-years from Earth and illuminated much of the galaxy. NASA has said that that gamma-ray was possibly the brightest ever to hit Earth since the beginning of human civilisation.
NASA said that the extragalactic outburst was 70 times brighter than any other such eruption recorded to date. According to a press note by NASA, the burst triggered detectors on numerous spacecraft, and observatories around the globe followed up. After combing through all of this data, astronomers can now characterize just how bright it was and better understand its scientific impact.
Eric Burns, an assistant professor of physics and astronomy at Louisiana State University in Baton Rouge said, "GRB 221009A was likely the brightest burst at X-ray and gamma-ray energies to occur since human civilization began." Mr Burns said that such events occur once every 10,000 years.
He revealed that the burst was so bright it effectively blinded most gamma-ray instruments in space, which means they could not directly record the real intensity of the emission. U.S. scientists were able to reconstruct this information from the Fermi data. They then compared the results with those from the Russian team working on Konus data and Chinese teams analyzing observations from the GECAM-C detector on their SATech-01 satellite and instruments on their Insight-HXMT observatory. Together, they prove the burst was 70 times brighter than any yet seen, NASA said.
Mr Burns added, "It is just an absolutely monstrous burst. It is extremely extraordinary; we've never seen anything remotely close to it."
"Being so close and so bright, this burst offered us an unprecedented opportunity to gather observations of the afterglow across the electromagnetic spectrum and to test how well our models reflect what's really happening in GRB jets," said Kate Alexander, an assistant professor in the department of astronomy at the University of Arizona in Tucson. "Twenty-five years of afterglow models that have worked very well cannot completely explain this jet," she said. "In particular, we found a new radio component we don't fully understand. This may indicate additional structure within the jet or suggest the need to revise our models of how GRB jets interact with their surroundings."
The burst also enabled astronomers to probe distant dust clouds in our own galaxy. As the prompt X-rays travelled toward us, some of them reflected off of dust layers, creating extended "light echoes" of the initial blast in the form of X-ray rings expanding from the burst's location. The X-ray Telescope on NASA's Neil Gehrels Swift Observatory discovered the presence of a series of echoes. Detailed follow-up by ESA's (the European Space Agency's) XMM-Newton telescope, together with Swift data, revealed these extraordinary rings were produced by 21 distinct dust clouds.
GRB 221009A is only the seventh gamma-ray burst to display X-ray rings, and it triples the number previously seen around one. The echoes came from dust located between 700 and 61,000 light-years away. The most distant echoes - clear on the other side of our Milky Way galaxy - were also 4,600 light-years above the galaxy's central plane, where the solar system resides.
Lastly, the burst offers an opportunity to explore a big cosmic question. "We think of black holes as all-consuming things, but do they also return power back to the universe?" asked Michela Negro, an astrophysicist at the University of Maryland, Baltimore County, and NASA's Goddard Space Flight Center in Greenbelt.
