On April 27, NASA’s Fermi and Swift satellites detected a record-setting burst from a dying star located in a nearby galaxy. Most likely the result of a massive supernova, it produced the highest-energy light ever detected by scientists.
Above image: The map above shows gamma-ray energies above 100 million electron volts (MeV). The first frame shows the sky during a three-hour interval just before the explosion. The second frame shows a three-hour interval starting 2.5 hours before the burst, and ending a half-hour into the event. Credit: NASA/DOE/Fermi LAT Collaboration.
The gamma-ray burst, called GRB 130427A, has wowed astronomers for a host of reasons. Not only was it freakishly powerful — one gamma-ray was measured at 94 billion electron volts (GeV) — but it was uncharacteristically long-lasting; the burst lasted for hours and was detectable for most of the day by Fermi’s Large Area Telescope (LAT). It produced 35 billion times the energy of visible light, and is about three times more powerful than the LAT’s previous record.
The explosion set a new record for the longest gamma-ray emission from a gamma-ray burst. And at 3.6 billion light years away, it was actually quite close. GRB 130427A falls within the closest 5% of all supernovas ever recorded. Celestial explosions like these are exceptionally rare, happening only once every million years or so per galaxy. They’re also very difficult to detect; the hyperfast jet emanating out from the ensuing black hole has be to positioned directly towards Earth. Needless to say, astronomers are not able to see the vast majority of GRB events.
This sequence shows high-energy (100 Mev to 100 GeV) gamma rays starting three minutes before the burst to 14 hours after. Following an initial one-second spike, the LAT emission remained relatively quiet for the next 15 seconds while Fermi's GBM instrument showed bright, variable lower-energy emission. Credit: NASA/DOE/Fermi LAT Collaboration.
Gamma-ray bursts happen when massive stars run out of fuel and collapse under their tremendous weight. As the core collapses into a newly-formed black hole, jets of material shoot outward through the collapsing star at nearly the speed of light. The jets continue into space, where they interact with gas shed by the star to produce bright afterglows.
These explosions wreak havoc to the immediate area. Any habitable planet located within several thousand light years are likely to be sterilized by such events.
"We have waited a long time for a gamma-ray burst this shockingly, eye-wateringly bright," noted Julie McEnery through an official statement. "The GRB lasted so long that a record number of telescopes on the ground were able to catch it while space-based observations were still ongoing." McEnery is a project scientist for the Fermi Gamma-ray Space Telescope at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Scientists will continue to monitor the area in an attempt to identify the ensuing supernova remnant.