New NASA Telescope Makes New Discovery: First Gamma-ray Only Pulsar

Thanks to NASA's new Fermi Gamma-ray Large Area Space Telescope, GLAST, recently launched into orbit, scientists have made a new important discovery-the first gamma-ray only pulsar. It is thought to be only the first discovered of many in the universe.

Pulsars have long been known to exist, but usually they emit a variety of wavelengths of energy, including visible light, and x-rays. Over 1800 other pulsars have already been catalogued. The gamma-ray only pulsar "will give us fundamental insights into how these collapsed stars work," says Peter Michelson, the principal investigator for Fermi's GLAST, from Stanford University.

The pulsar was found in the supernova remnant known as CTA-1. It is 4600 light-years away and is in the Cepheus constellation. It emits an energy beam gamma-rays that sweeps through space about 3 times per second that is likened to a blinking light. The pulsar is thought to be 10,000 years old and its energy emissions are 1,000 times stronger than that of the sun.

The GLAST is thought to have been able to pick up the gamma-ray energy because "we think the region that emits the pulsed gamma-rays is broader than that responsible for pulses of lower-energy radiation," explains Alice Harding of NASA's Goddard Space Flight Center. "The radio beam probably never swings toward Earth, so we never see it. But the wider gamma-ray beam does sweep our way."

Pulsars are unique and interesting interstellar objects that result as the remains of an exploded star, or supernova. It is essentially a crushed core of the original star known as a neutron star that spins rapidly emitting various wavelengths of remaining energy. This energy is the result of the magnetic fields and the charged particles that stream outward from its magnetic poles. The streams are so intense because they are powered by the rapid rotation.

It would seem that the pulsar must lie in the center of the supernova, but in the case of CTA-1 and many other pulsars, the supernova explosion "kicks" the neutron star core outward and sets in travelling through space away from the center of the explosion. It is thought that the CTA-1 pulsar is moving at about one million mph, as stated in Universe Today.

GLAST is a joint project developed by U.S. Department of Energy with contributions from academic partnerships in France, Germany, Italy, Japan, Sweden, and the USA. It works by scanning the entire sky every three hours, detecting photons with energies 20 million to 300 billion times that of visible light. It collects approximately one gamma-ray per minute which is enough for scientists to piece together a comprehensive set of behaviors of pulsars. The GLAST is quickly becoming one of the most important tools in astronomy.

Sources:

Rob Gutro, "NASA's Fermi Telescope Discovers First Gamma-Ray-Only Pulsar", NASA

Nancy Atkinson, "Fermi Telescope Makes First Big Discovery: Gamma Ray Pulsar", Universe Today

Staff, "Spacecraft discovers first pure gamma-ray pulsar", Astronomy

GLAST Science Writer's Guide, "Exploring the Extreme Universe", NASA