June 13, 2012
During a powerful solar blast on March 7, NASA’s Fermi Gamma-ray Space Telescope detected the highest-energy light ever associated with an eruption on the Sun. The discovery heralds Fermi’s new role as a solar observatory, a powerful new tool for understanding solar outbursts during the Sun’s maximum period of activity.
A solar flare is an explosive blast of light and charged particles. The powerful March 7 flare, which earned a classification of X5.4 based on the peak intensity of its X-rays, is the strongest eruption so far observed by Fermi’s Large Area Telescope (LAT). The flare produced such an outpouring of gamma rays – a form of light with even greater energy than X-rays – that the Sun briefly became the brightest object in the gamma-ray sky.
“For most of Fermi’s four years in orbit, its LAT saw the Sun as a faint, steady gamma-ray source thanks to the impacts of high-speed particles called cosmic rays,” said Nicola Omodei, an astrophysicist at Stanford University. “Now we’re beginning to see what the Sun itself can do.”
Omodei described Fermi’s solar studies to journalists today at the 220th meeting of the American Astronomical Society in Anchorage, Alaska.
The LAT was designed and built by an international collaboration with members from France, Italy, Japan, Sweden and the United States. SLAC managed the construction and integration of the telescope, and the Kavli Institute for Particle Astrophysics and Cosmology is the lead for ongoing operation of the instrument.
Visit NASA online for the full announcement, plus videos.