Credit: NASA/DOE/Fermi LAT Collaboration
When a massive star dies, it often leaves behind a tiny, extremely dense cinder called a neutron star. Neutron stars are produced by the collapse of the star's core, producing a supernova explosion, and are born with strong magnetic fields and rapid spins. The strong magnetic fields and rapid spin produce beams of radiation which sweep through space. Astronomers have discovered about 1,800 such pulsars through their periodic radio emission. But pulsars emit a broad range of radiation from radio waves up through extremely high energy gamma rays. The Fermi Gamma-Ray Space Telescope, launched about 1 year ago, is the first gamma-ray observatory powerful enough to discover pulsars from their gamma-ray emission alone. The image above shows the Fermi all-sky map from Fermi's Large Area Telescope (LAT), along with the locations of gamma-ray pulsars detected by Fermi. Some of these have been already detected via their radio emission, but astoundingly Fermi has been able to detect 16 new gamma-ray pulsars (in only 5 months of observation) which have never before been identified. These pulsars were detected by astronomers using "blind" searches for periodic signals in the gamma-ray emission detected by the LAT. These LAT detections allow astronomers to better constrain the manner in which pulsars are formed and better understand how the pulsars interact with their environments.
Published: July 13, 2009
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Page Author: Dr. Michael F. Corcoran
Last modified Friday, 20-Apr-2012 15:20:51 EDT