About three times a second, a 10,000-year-old stellar corpse sweeps a beam of gamma-rays toward Earth. This object, known as a pulsar, is the first one known to "blink" only in gamma rays, and was discovered by the Large Area Telescope (LAT) onboard NASA's Fermi Gamma-ray Space Telescope.
"This is the first example of a new class of pulsars that will give us fundamental insights into how stars work," says Stanford University's Peter Michelson, principal investigator for the LAT.
The gamma-ray-only pulsar lies within a supernova remnant known as CTA 1, which is located about 4,600 light-years away in the constellation Cepheus. Its lighthouse-like beam sweeps Earth's way every 316.86 milliseconds and emits 1,000 times the energy of our sun. These results appear in the Oct. 16 edition of Science Express.
A pulsar is a rapidly spinning neutron star, the crushed core left behind when a massive sun explodes. Astronomers have cataloged nearly 1,800 pulsars. Although most were found through their pulses at radio wavelengths, some of these objects also beam energy in other forms, including visible light and X-rays.
Unlike previously discovered pulsars, the source in CTA 1 appears to blink only in gamma-ray energies, offering researchers a new way to study the stars in our universe. Scientists think CTA1 is only the first of a large population of similar objects.
"The LAT provides us with a unique probe of the galaxy's pulsar population, revealing objects we would not otherwise even know exist," says Fermi telescope project scientist Steve Ritz.
Source: Xinhua
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