Gamma-ray Astronomy

Gamma-ray astronomy is the astronomical study of the cosmos with gamma rays. Gamma-rays are the most energetic form of "light" (electromagnetic radiation) that travel across the universe, and gamma-rays thus have the smallest wavelength of any wave in the electromagnetic spectrum.

Gamma-rays are created by celestial events such as supernova explosions, destruction of positrons, creation of black holes and even the decay of radioactive material (gamma decay) in space. For example, supernova SN 1987A emitted an "afterglow" of gamma-ray photons from the decay of newly-made radioactive cobalt-56 ejected into space in a cloud, by the explosion. Most astronomical gamma-rays are thought to be produced not from radioactive decay, however, but from the same type of accelerations of electrons, and electron-photon interactions, that produce X-rays in astronomy (but occurring at a higher energy in the production of gamma-rays). Astronomical literature tends to hyphenate "gamma-ray" by analogy with the term "X-ray."