gamma-ray bursts

gamma-ray bursts

Intense flashes of hard X-rays or gamma rays, detected at energies up to one million electronvolts. They are of short duration (0.1–1000 seconds) and were discovered by US Air Force satellites in 1967 but not declassified until 1973. There are sharp temporal features in the burst time profile; this allows the measurement of differences in arrival times of wavefronts of the order of a few milliseconds over baselines separated by hundreds of light-seconds. For the strongest and most rapidly varying bursts, such measurements yield angular resolutions of the order of arc seconds. The most intense burst observed so far lies within the supernova remnant N49 in the Large Magellanic Cloud. The BATSE experiment on the Compton Gamma Ray Observatory has detected hundreds of γ-ray bursts, averaging about one per day. Measurements have revealed that the distribution of the bursts is consistent with isotropy: they are uniformly distributed across the sky. Their origin still remains a mystery. γ-ray emission lines in their spectra may be related to annihilation radiation redshifted by the strong gravitational field of a neutron star, and γ-ray absorption features to cyclotron absorption in intense magnetic fields. The rapid temporal structure, including the periodic emission, is generally assumed to point to neutron star origins for γ-ray bursts, although sources at cosmological distances cannot be ruled out. The most probable energy source is thought to be either gravitational or nuclear in origin.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

gamma-ray bursts

[′gam·ə ‚rā ‚bərsts]
(astronomy)
Intense blasts of soft gamma rays of unknown origin, which range in duration from a tenth of a second to tens of seconds and occur several times a year from sources widely distributed over the sky.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Without such detections -- in particular, at longer wavelengths such as X-rays or optical light -- it is very difficult to determine the precise location of events that produce gamma-ray bursts.
That said, it is also worth noting the observation of this jet also bolsters the popular theory that gamma-ray bursts are produced from neutron star mergers.
In addition to a previously published special issue, "Gamma-Ray Bursts in the Swift and Fermi Era," which discussed GRB work related to the Swift and Fermi missions, here we continue collecting reviews and research articles on GRBs and their afterglows.
Beijing, Ramadan 20, 1438, June 15, 2017, SPA -- China launched its first X-ray space telescope, which will hunt for black holes, pulsars and gamma-ray bursts, dpa reported.
Each year, astronomers observe several hundred of these explosions, known as gamma-ray bursts, but this marks the first time scientists have spotted a burst's remnant radiance before detecting the burst itself.
Gamma-ray bursts (GRBs) typically last less than a minute and Swift detects one event about twice a week.
Farley Ferrante, a graduate student in SMU's Department of Physics, who monitored the observations along with two astronomers in Turkey and Hawaii, said gamma-ray bursts are believed to be the catastrophic collapse of a star at the end of its life.
Gamma-ray bursts interest him because they're the most extreme explosions human beings know about, he said.
The most powerful explosions in the universe are brilliant flashes of light called gamma-ray bursts. If you happened to fly through the neighborhood of a gamma-ray burst, you couldn't miss the flare--it would be brighter than a million trillion suns.
Using a robotic telescope at the ESO La Silla Observatory, astronomers have measured the velocity of the explosions known as gamma-ray bursts. The material is traveling at the extraordinary speed of more than 99.999 percent of the velocity of light, the maximum speed limit in the Universe.