GAMMA-RAY BURSTS & SPACE WEATHER
Gamma-ray Burst definition: Intense high-energy electromagnetic radiation, lasting between a fraction of a second and several minutes, emanating from distant regions of the universe.1
A well-done visual history of Gamma-ray Bursts appears at Visual History of GRBs.
BATSE was a high energy astrophysics experiment in orbit around Earth on NASA's Compton Gamma-Ray Observatory. The primary objective of BATSE was to study the phenomenon of gamma-ray bursts, although the detectors also recorded data from pulsars, terrestrial gamma-ray flashes, soft gamma repeaters, black holes, and other exotic astrophysical objects.
The Compton Gamma Ray Observatory was removed from orbit by NASA on 4 June, 2000 bringing to an end the successful 9-year CGRO mission. During its operation, BATSE recorded 8000 triggered events.
The following image shows the locations of a total of 2704 Gamma-Ray Bursts recorded with the Burst and Transient Source Experiment on board NASA's Compton Gamma-Ray Observatory during the nine-year mission. Credit: NSSTC (National Space, Science, and Technology Center).
Image above: "The projection is in galactic coordinates; the plane of the Milky Way Galaxy is along the horizontal line at the middle of the figure. The burst locations are color-coded based on the fluence, which is the energy flux of the burst integrated over the total duration of the event. Long duration, bright bursts appear in red, and short duration, weak bursts appear in purple. Grey is used for bursts for which the fluence cannot be calculated due to incomplete data."2
The next image portrays the Birth of a Gamma-ray Burst.
Image above: Stars shine by burning hydrogen. The process is called nuclear fusion. Hydrogen burning produces helium "ash." As the star runs out of hydrogen (and nears the end of its life), it begins burning helium. The ashes of helium burning, such as carbon and oxygen, also get burned. The end result of this fusion is iron. Iron cannot be used for nuclear fuel. Without fuel, the star no longer has the energy to support its weight. The core collapses. If the star is massive enough, the core will collapse into a black hole. The black hole quickly forms jets; and shock waves reverberating through the star ultimately blow apart the outer shells.
Gamma-ray bursts are the beacons of star death and black hole birth.
Credit: Nicolle Rager Fuller/NSF.
Seth Borenstein posted an AP article on 11/21/2013 with the enticing title: 'Monster' Gamma Ray Burst Zipped By Earth, Astronomers Say. Well worth a read!
A GRB event, GRB 101225A, exploded on December 25, 2010 and produced high-energy emission for at least two hours. Subsequently nicknamed the "Christmas burst," the event's distance was unknown, which led two teams to arrive at radically different physical interpretations.
One group concluded the blast was caused by an asteroid or comet falling onto a neutron star within our own galaxy. Another team determined that the burst was the outcome of a merger event in an exotic binary system located some 3.5 billion light-years away.
"We now know that the Christmas burst occurred much farther off, more than halfway across the observable universe, and was consequently far more powerful than these researchers imagined," said astronomer Andrew Levan.
The following video produced by NASA uses animation to demonstrate three different possible causes for the event GRB101225A.
Now . . . let's take a little tour into a collection of: