The James Webb Space Telescope and other international observatories have observed supernovae as old as 13 billion years. On Tuesday, the European Space Agency (ESA) announced the sighting of a gamma-ray burst from a star that exploded when the universe was only 730 million years old. The Webb telescope also detected the supernova’s host galaxy.
Before this observation, the oldest recorded supernova occurred when the universe was 1.8 billion years old. This is a difference of more than a billion years.
You can see the gamma-ray burst in the image below. It’s the small red dot in the center of the zoom-in box on the right.
“This observation also shows that we can use the web to find individual stars when the universe was only 5 percent of its current age,” co-author Andrew Levan wrote in an ESA press release. “In the last 50 years there have only been a handful of gamma-ray bursts that have been detected in the first billion years of the universe. This particular event is very rare and very exciting.”
The researchers discovered that the 13 billion-year-old explosion had many characteristics in common with modern, nearby supernovae. Although this may not seem surprising, scientists expected a more profound difference. This is because the early stars probably contained less heavy elements, were more massive and did not live as long. “We went in with an open mind,” said co-writer Niall Tanvir. “And look, the web showed that this supernova looks exactly like modern supernovae.”
Detection was an international relay race. First, Neal Gehrels of NASA’s Swift Observatory noted the location of the X-ray source. (This enabled Webb to make subsequent observations that determined his distance). Then, observations by the Nordic Optical Telescope on the Canary Islands in Spain indicated that the gamma ray burst may be very distant. A few hours later, the Very Large Telescope at the European Southern Observatory in Chile estimated its age: 730 million years after the Big Bang. According to ESA, all this happened in less than 17 hours.
The team behind the observations has been given the go-ahead to spend more time with Webb to study gamma-ray bursts from the early universe and the galaxies behind them. “That brightness will help us see more of the Webb and give us a ‘fingerprint’ of the galaxy,” Levan predicted.
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