Source Identified As Giant Flare On Surface Of Neutron Star

Scientists have detected a flash of light from across the Galaxy so powerful that it bounced off the Moon and lit up the Earth's upper atmosphere. The flash was brighter than anything ever detected from beyond our Solar System and lasted over a tenth of a second. NASA and European satellites and many radio telescopes detected the flash and its aftermath on December 27, 2004. Two science teams report about this event at a special press event today at NASA headquarters. A multitude of papers are planned for publication.

The scientists said the light came from a "giant flare" on the surface of an exotic neutron star, called a magnetar. The apparent magnitude was brighter than a full moon and all historical star explosions. The light was brightest in the gamma-ray energy range, far more energetic than visible light or X-rays and invisible to our eyes.

Such a close and powerful eruption raises the question of whether an even larger influx of gamma rays, disturbing the atmosphere, was responsible for one of the mass extinctions known to have occurred on Earth hundreds of millions of years ago. Also, if giant flares can be this powerful, then some gamma-ray bursts (thought to be very distant black-hole-forming star explosions) could actually be from neutron star eruptions in nearby galaxies.

NASA's newly launched Swift satellite and the NSF-funded Very Large Array (VLA) were two of many observatories that observed the event, arising from neutron star SGR 1806-20, about 50,000 light years from Earth in the constellation Sagittarius.

"This might be a once-in-a-lifetime event for astronomers, as well as for the neutron star," said Dr. David Palmer of Los Alamos National Laboratory, lead author on a paper describing the Swift observation. "We know of only two other giant flares in the past 35 years, and this December event was one hundred times more powerful." 

FMI: http://www.nasa.gov/mpg/108531main_flashcam0001_NASA%20WebV_1.mpg