Monster Gamma-Ray Burst Blasts Nearby Universe as Star Explodes

Scientists may have just witnessed one of the largest gamma-ray bursts ever detected in our cosmic neighborhood. They've detected a violent burst of gamma radiation in the relatively nearby universe, which tells them a bit more about these monsters gamma-ray bursts in general.

Gamma-ray bursts are associated with exploding massive stars. When astronomers observe these bursts, though, they never see the original star itself; it's far too dim to be seen from a distance during the actual action. Yet once the star dies, astronomers can see the exploding star as a supernova.

So how did astronomers first spot this burst of gamma radiation? The Swift satellite monitors space and discovers about 100 gamma-ray bursts each year. In April, it picked out the massive outburst.

"We suddenly saw a gamma-ray bursts that was extremely bright-a monster gamma-ray burst," said Daniele Malesani, one of the researchers, in a news release. "This is one of most powerful gamma-ray bursts we have observed with the Swift satellite."

After the initial burst, the researchers followed the afterglow. In this case, it was so powerful that the scientists could observe this afterglow for several months. They analyzed its light and studied its spectral composition, which told them about the properties of the original star.

So what was the star exactly? It was a giant with a mass that's about 20 to 30 times the mass of our own sun. Its size, though, is only about three to four times that of our sun, which means that it's extremely compact. These types of stars are called Wolf-Rayet stars.

That's not all the researchers discovered, though. They also were able to find out that the gamma-ray burst exploded when the universe was 9.9 billion years old. It took the light 3.75 billion years to reach us on Earth.

The findings could tell researchers a little more about gamma-ray bursts and the life and death of stars.

The research and observations are published in the journal Science.