Gamma-ray Bursts: Some of the Brightest Explosions in the Universe Detected by NASA's Fermi Mission

Gamma-ray bursts (GRBs) are extremely energetic and rare events, considered to be the brightest, or most luminous, explosions in the universe.

Lasting anywhere from a few milliseconds to several hours, GRBs involve a sudden and intense release of gamma-rays—the most energetic form of electromagnetic radiation, which has a very short wavelength—traveling at near-light-speed in vast jets.

This initial burst is then typically followed by a longer-lasting emission of longer wavelength radiation, including X-rays, ultraviolet light, visible light and radio waves.

First detected in 1967, GRBs have only been identified in distant galaxies, billions of light-years from our planet. But they are so energetic we are able to detect them using observatories such as NASA's Fermi Gamma-ray Space Telescope, which was launched in June 2008.

An international team of scientists has now created a catalog containing 186 of the highest-energy GRBs detected by Fermi—published in The Astrophysical Journal—which will aid future research into these extreme events.

"Each burst is in some way unique," Magnus Axelsson, an astrophysicist at Stockholm University in Sweden and an author of the study, said in a statement. "It's only when we can study large samples, as in this catalog, that we begin to understand the common features of GRBs. These, in turn, give us clues to the physical mechanisms at work."

It is thought that GRBs occur as the result of two different cataclysmic events: Some happen after certain types of massive stars explode as supernovae leaving behind black holes or neutron stars—extremely dense remnant cores. Meanwhile, other GRBs occur when two neutron stars merge, an event which we now know produces gravitational waves—ripples in the fabric of space-time.

Here are three examples of particularly intriguing GRBs contained in the new Fermi catalog:

GRB 080916C

Not only is GRB 080916C the most distant known gamma-ray burst—occurring 12.2 billion light-light-years away in the constellation Carina—it is also the most powerful ever recorded, according to NASA. In fact, scientists estimate that the power of the explosion was equivalent to around 9,000 supernovae. Lasting for 23 minutes, the GRB occurred when the universe was less than 2 billion years old, but it is so far away that its light has taken billions of years to reach us.

GRB 130427A

This GRB—which occurred around 3.8 billion light-years away in the constellation Leo—provided the highest-energy individual gamma-ray detected by Fermi with a reading of 94 billion electron volts (GeV). Furthermore, this event also produced the most gamma rays above with energies above 10 GeV—17.

GRB 160623A

This GRB is unusual because it is the longest-lasting of all those detected by the Fermi. Identified on June 23, 2016, in the constellation Cygnus, the telescope recorded the burst for around 10 hours at high energies.

NASA, Fermi, gamma-ray bursts
Green dots show the locations of 186 gamma-ray bursts observed by the Large Area Telescope (LAT) on NASA’s Fermi satellite during its first decade. NASA/DOE/Fermi LAT Collaboration
Gamma-ray Bursts: Some of the Brightest Explosions in the Universe Detected by NASA's Fermi Mission | Tech & Science