NASA’s Fermi telescope sees mother of all gamma-rays blastFebruary 20th, 2009 - 5:41 pm ICT by IANS
Washington, Feb 20 (IANS) The first gamma-ray burst to be seen in high-resolution from NASA’s Fermi Gamma-ray Space Telescope had the greatest total energy, the fastest motions and the highest-energy initial emissions ever recorded.
“We were waiting for this one,” said Peter Michelson, the principal investigator on Fermi’s Large Area Telescope at Stanford University. “Burst emissions at these energies are still poorly understood, and Fermi is giving us the tools to understand them.”
Gamma-ray bursts are the universe’s most luminous explosions. Astronomers believe most occur when exotic massive stars run out of nuclear fuel. As a star’s core collapses into a black hole, jets of material — powered by processes not yet fully understood — blast outward at nearly the speed of light.
The jets bore all the way through the collapsing star and continue into space, where they interact with gas previously shed by the star and generate bright afterglows that fade with time.
This explosion, designated GRB 080916C, occurred at 7:13 p.m. on Sept 15 last year in the constellation Carina. Fermi’s other instrument, the Gamma-ray Burst Monitor, simultaneously recorded the event.
Together, the two instruments provide a view of the blast’s initial, or prompt, gamma-ray emission from energies between 3,000 to more than five billion times that of visible light.
With the distance in hand, Fermi team members showed that the blast exceeded the power of approximately 9,000 ordinary supernovae, if the energy was emitted equally in all directions, said a Stanford release.
The team’s results appeared in the Friday online edition of Science.