Gamma-ray burst breaks record for biggest cosmic explosion
Washington – Cosmic explosion caused by the death of a star in a distant galaxy became the focus of astronomers around the world after it occurred in April.
The explosion, known as a gamma-ray burst and designated GRB 130427A, has topped the charts as one of the brightest ever seen.
A trio of NASA satellites, working in concert with ground-based robotic telescopes, captured never-before-seen details that challenge current theoretical understandings of how gamma-ray bursts work.
“We expect to see an event like this only once or twice a century, so we’re fortunate it happened when we had the appropriate collection of sensitive space telescopes with complementary capabilities available to see it,” Paul Hertz, director of NASA’s Astrophysics Division in Washington, said.
Gamma-ray bursts are the most luminous explosions in the cosmos, thought to be triggered when the core of a massive star runs out of nuclear fuel, collapses under its own weight, and forms a black hole. The black hole then drives jets of particles that drill all the way through the collapsing star and erupt into space at nearly the speed of light.
Gamma-rays are the most energetic form of light. Hot matter surrounding a new black hole and internal shock waves produced by collisions within the jet are thought to emit gamma-rays with energies in the million-electron-volt (MeV) range, or roughly 500,000 times the energy of visible light.
The most energetic emission, with billion-electron-volt (GeV) gamma rays, is thought to arise when the jet slams into its surroundings, forming an external shock wave.
NASA’s Swift Gamma-ray Burst Mission detected the burst almost simultaneously with the GBM and quickly relayed its position to ground-based observatories.