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NASA spots 'gamma ray-only' pulsar

Astronomers have discovered nearly 1,800 neutron stars. These
collapsed cores of massive stars are among the most bizarre denizens
of the cosmic zoo, each one packing more than a Sun's worth of mass
into a city-sized sphere. [5]

NASA's Fermi Gamma-ray Space Telescope (formerly known as GLAST)
has spied the first "gamma ray-only" pulsar - a 10,000 year-old stellar
remnant which uniquely doesn't appear to emit pulses at either radio,
visible light or X-ray wavelengths in common with the 1,800 or so similar
objects catalogued to date. [1]

NASA said the gamma-ray-only pulsar lies within a supernova remnant
known as CTA 1, about 4,600 light-years away from Earth in the
constellation Cepheus. [2]

Typically, supernova remains include the dead star's collapsed core --
known as a neutron star because its protons and electrons have
combined to form neutrons. Sometimes the neutron star is spinning,
which causes jets of particles to stream out above their magnetic poles,
producing powerful beams of light that appear as flashes as the star
rotates. These are known as pulsars, and their beams have been found
in radio wavelengths, X-ray and, now for the first time, in gamma rays as
well. [3]

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. However, the source in CTA 1 only
pulses at gamma-ray energies. [4]

Studies of these neutron stars will provide clues that will help
astronomers piece together the life cycle of neutron stars, and how
pulsars emit their beamed radiation. [5]

[1] No radio broadcasts from neutron star The Register  17th October 2008

[2] First gamma-ray-only pulsar is discovered UPI Oct. 16, 2008
[3] Dead Star Flings Gamma Rays in Pulses Discovery News Oct. 16,
2008
[4] NASA's Fermi Telescope Discovers First Gamma-Ray-Only Pulsar
MatchWatch Oct. 16, 2008
[5] NASA Satellite Discovers New Type of Pulsar SkyandTelescope.com
Oct 2008
"Victoria crater" Image Credit: NASA/JPL/Cornell  SPACE