In October 2022, an extremely bright flash caught the attention of the Gemini South telescope in Chile. It was quickly determined that it was a the brightest ever seenhence its nickname: the Brightest Of All Time (the BOAT).
Now a group of researchers examined the event with the Webb Space Telescope and concluded that the cause of BOAT was a supernova: an explosive, bright death of a star. Researchers also looked for heavy elements like gold and platinum but saw no signs of them, leaving the question of their origins just as open as before. The team’s research is published today in natural astronomy.
Heavy elements are produced by merging neutron stars – at least some of them are. The heavy elements in the universe are too abundant for such stellar mergers to explain them all. Even after two stars in a binary system explode, leaving behind the dense shells that are neutron stars, “it can take billions and billions of years for the two neutron stars to slowly approach each other and end up merging,” according to Peter Blanchard, a researcher. astronomer at Northwestern University and lead author of the study, at the university release.
“But observations of very old stars indicate that some parts of the universe were enriched in heavy metals before most binary neutron stars had time to merge,” Blanchard added. “This points us toward an alternative channel.”
Gamma-ray bursts come in two types: long duration and short duration. Short bursts are associated with the merger of stars and the formation of black holes, according to NASA, while longer bursts are associated with stellar deaths. The BOAT is firmly in the latter camp.
The team intentionally waited several months after the BOAT was detected to turn the Webb telescope toward it. That’s because the explosion was so bright – and that brightness persisted for so long – that we had to wait until the event faded to spot any sign of the supernova that carried it.
Using the telescope’s Near-Infrared Spectrograph (NIRSpec), the team examined elements typically seen in supernovae. The signal was not particularly bright, indicating that the supernova that produced the brightest gamma-ray burst ever seen was not superlative in itself.
“This event is particularly exciting because some had hypothesized that a bright gamma-ray burst like BOAT could produce lots of heavy elements like gold and platinum,” said Ashley Villar, co-author of the study. , astrophysicist at Harvard University and the Center for Astrophysics | Harvard & Smithsonian, in the press release. “If they were right, the BOAT should have been a gold mine. It is really striking that we have seen no evidence of the presence of these heavy elements.
Long gamma bursts are those that last more than two seconds. The BOAT lasted 10 hours, according to ScienceNews. But if we are technical, the BOAT is not In fact the boat. But it is “probably the brightest burst of x-ray and gamma-ray energy that has occurred since the beginning of human civilization,” according to Eric Burns, an astrophysicist at California State University. Louisiana and co-author of a study. study describing the signal.
A year and changes after the signal, a scientific collaboration determined that the BOAT was emitting gamma rays with energies reaching up to 13 teraelectronvolts—the same energy as the Large Hadron Collider at CERN during his second race.
Scientists continue to sift through the wealth of data provided by BOAT. Last June, a group reported the structure of the burst jet, which could lead physicists to rework their models of jet structure. For all its accolades, the BOAT is not the biggest explosion ever seen in space; That title belongs to AT2021lwx, a nearly 8 billion-year-old explosion from a distant black hole and the cloud of gas surrounding it.
Astronomers will likely see more explosions like this – and like BOAT’s – when next-generation observatories come online. One of the most high-profile installations is the Vera Rubin Observatory in Chile’s Atacama Desert, which will use a 3.2 billion pixel camera to collect terabytes of data on the southern sky every night.
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