3. Space News | Observations by two of the world's largest telescopes provide strong evidence that a peculiar type of exploding star may be the origin of elusive gamma-ray bursts that have puzzled scientists for more than 30 years.
A team of astronomers from Italy, Japan, Germany and the United States, including the University of California, Berkeley, conclude from observations with the Keck and Subaru telescopes in Hawaii that naked carbon/oxygen stars that flatten as they collapse into a black hole are good candidates for the source of gamma-ray bursts.
Though astronomers have observed a couple of bursts associated with this type of supernova - a Type Ic supernova sometimes called a hypernova - the theory of how a hypernova produces gamma rays is still speculative.
The new observations, though not a smoking gun, provide a major piece of evidence that the theory, called the collapsar model, is correct.
The model explains how an asymmetric exploding star produces a tight beam of matter and energy out of each pole that generates an intense burst of gamma rays, while the absence of a hydrogen and helium envelope would allow the blast to escape.
"It appears that to produce a gamma-ray burst, a core-collapse supernova needs to be both asymmetric in its explosion mechanism, so that there is a natural axis along which matter can more easily squirt, and free of a hydrogen envelope, so that the jet doesn't have to pummel through a lot of material," said co-author Alex Filippenko, UC Berkeley professor of astronomy.
Source For Full Article : http://www.spacedaily.com/news/gamma-05h.html
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