The brightest gamma-ray burst ever recorded recently illuminated a distant galaxy, and astronomers have dubbed it the BOAT, for the brightest of all time.
“We use the ship emoji a lot when we talk about it” on the Slack messaging app, says astronomer Jillian Ratinejad of Northwestern University in Evanston, Illinois.
Gamma ray bursts are energetic explosions that are fired when a massive star dies and leaves behind a black hole or neutron star (Serial Number: 11/20/19; Serial Number: 8/2/21). The collapse triggers jets of gamma rays that move away from the poles of the old star. If those jets point directly at Earth, astronomers can see them as a gamma-ray burst.
East new popofficially named GRB 221009A, it was likely caused by a supernova that gave rise to a black hole in a galaxy about 2 billion light-years from Earth, researchers announced Oct. 13. Astronomers believe that it released as much energy as about three suns by converting all of its energy. mass to pure energy.
NASA’s Neil Gehrels Swift Observatory, a gamma-ray telescope in space, automatically detected the explosion on October 9 at around 10:15 a.m. EDT and immediately alerted astronomers. that something strange was happening.
“At the time, when it exploded, it seemed a little strange to us,” says Penn State astrophysicist Jamie Kennea, who is Swift’s chief of science operations. The position of the explosion in the sky seemed to line up with the plane of the Milky Way. So at first, Kennea and his colleagues thought it was inside our own galaxy, and unlikely to be something as dramatically energetic as a gamma-ray burst. If an outburst like this were to occur within the Milky Way, it would be visible to the naked eye, which was not the case.
But soon Kennea learned that NASA’s Fermi Gamma-ray Space Telescope had also seen the flash, and that it was one of the brightest things the telescope had ever seen. A new look at the Swift data convinced Kennea and his colleagues that the flash was the brightest gamma-ray burst seen in 50 years of observing these rare bursts.
“It’s pretty exceptional,” says Kennea. “He is head and shoulders above the rest.”
After BOAT’s bona fide confirmation of the outburst, a term coined by Ratinejad’s adviser, Northwestern astronomer Wen-fai Fong, other astronomers were quick to take a look. Within days, scientists around the world were able to glimpse the explosion with telescopes in space and on the ground, in almost all types of light. Even some radio telescopes typically used as lightning detectors saw a sudden disturbance associated with GRB 221009Asuggesting that the blast ripped electrons from atoms in Earth’s atmosphere.
In the hours and days after the initial explosion, the blast subsided and gave way to a still relatively bright glow. Eventually, astronomers hope to see it fade further, replaced by glowing waves of material in the supernova remnant.
The extreme brightness was likely due, at least in part, to GRB 221009A’s relative proximity, Kennea says. A couple of billion light-years may seem far away, but the average gamma-ray burst is more than 10 billion light-years away. It was also probably intrinsically bright, though there hasn’t been time to figure out why.
Studying the burst as it changes “is probably going to challenge some of our assumptions about how gamma-ray bursts work,” says Kennea. “I think people who are gamma-ray burst theorists will be inundated with so much data that this will change theories that they thought were pretty solid.”
GRB 221009A will move behind the sun from Earth’s perspective beginning in late November, temporarily shielding it from view. But because its glow is still so bright now, astronomers are hopeful that they will be able to see it when it becomes visible again in February.
“I’m very excited for a few months from now when we have all the beautiful data,” Ratinejad says.