Gamma rays are defined as photons with energies greater than 100 keV.

Gamma rays can be produced by a variety of astrophysical processes, including the interactions of cosmic rays with matter, the decay of radioactive isotopes, and the annihilation of particles.

Black holes are the most powerful gamma-ray sources in the universe. They can produce gamma rays through a variety of processes, including the accretion of matter onto the black hole, the jets of particles that are ejected from the black hole, and the Hawking radiation that is emitted from the black hole's event horizon.

The Compton Gamma-Ray Observatory was the first gamma-ray telescope. It was launched in 1991 and operated until 2000. The Compton Gamma-Ray Observatory made a number of important discoveries, including the first detection of gamma rays from a supernova.

The Fermi Gamma-ray Space Telescope is the current gamma-ray telescope. It was launched in 2008 and is still in operation. The Fermi Gamma-ray Space Telescope has made a number of important discoveries, including the first detection of gamma rays from a dark matter candidate.

GRB 130427A is the most powerful gamma-ray burst ever detected. It was detected on April 27, 2013, by the Swift Gamma-Ray Burst Mission. GRB 130427A released more energy in gamma rays than any other gamma-ray burst ever detected.

The most distant gamma-ray burst ever detected is GRB 090423. It was detected on April 23, 2009, by the Swift Gamma-Ray Burst Mission. GRB 090423 is located about 40 billion light-years from Earth.

The collapsar model is the leading theory that explains the origin of gamma-ray bursts. The collapsar model proposes that gamma-ray bursts are produced by the collapse of a massive star. When a massive star collapses, it forms a black hole. The black hole then accretes matter from the surrounding star, which produces a powerful jet of particles. The jet of particles then interacts with the surrounding gas, which produces gamma rays.

A gamma-ray burst is a sudden and intense burst of gamma rays. Gamma-ray bursts are the most powerful explosions in the universe. They can release more energy in a few seconds than the Sun will release in its entire lifetime.

A gamma-ray flare is a long-lasting emission of gamma rays that follows a gamma-ray burst. Gamma-ray flares can last for hours or even days. They are thought to be produced by the interaction of the jet of particles from the gamma-ray burst with the surrounding gas.

A gamma-ray storm is a long-lasting emission of X-rays that follows a gamma-ray burst. Gamma-ray storms can last for weeks or even months. They are thought to be produced by the interaction of the jet of particles from the gamma-ray burst with the surrounding gas.

A gamma-ray storm is a long-lasting emission of radio waves that follows a gamma-ray burst. Gamma-ray storms can last for weeks or even months. They are thought to be produced by the interaction of the jet of particles from the gamma-ray burst with the surrounding gas.

A gamma-ray storm is a long-lasting emission of optical light that follows a gamma-ray burst. Gamma-ray storms can last for weeks or even months. They are thought to be produced by the interaction of the jet of particles from the gamma-ray burst with the surrounding gas.

A gamma-ray storm is a long-lasting emission of infrared light that follows a gamma-ray burst. Gamma-ray storms can last for weeks or even months. They are thought to be produced by the interaction of the jet of particles from the gamma-ray burst with the surrounding gas.

A gamma-ray storm is a long-lasting emission of ultraviolet light that follows a gamma-ray burst. Gamma-ray storms can last for weeks or even months. They are thought to be produced by the interaction of the jet of particles from the gamma-ray burst with the surrounding gas.