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In astrophysics, gamma rays are conventionally defined as having photon energies above 100 keV and are the subject of gamma-ray astronomy, while radiation below 100 keV is classified as X-rays and is the subject of X-ray astronomy. Gamma rays are ionizing radiation and are thus hazardous to life.
The history of gamma-ray [1] began with the serendipitous detection of a gamma-ray burst (GRB) on July 2, 1967, by the U.S. Vela satellites. After these satellites detected fifteen other GRBs, Ray Klebesadel of the Los Alamos National Laboratory published the first paper on the subject, Observations of Gamma-Ray Bursts of Cosmic Origin. [2]
No gamma-ray bursts from within our own galaxy, the Milky Way, have been observed, [161] and the question of whether one has ever occurred remains unresolved. In light of evolving understanding of gamma-ray bursts and their progenitors, the scientific literature records a growing number of local, past, and future GRB candidates.
Gamma rays, at the high-frequency end of the spectrum, have the highest photon energies and the shortest wavelengths—much smaller than an atomic nucleus. Gamma rays, X-rays, and extreme ultraviolet rays are called ionizing radiation because their high photon energy is able to ionize atoms, causing chemical reactions. Longer-wavelength ...
The LD 50 figure assumes that the individuals did not receive other injuries or medical treatment. In the 1950s, the LD 50 for gamma rays was set at 3.5 Gy, while under more dire conditions of war (a bad diet, little medical care, poor nursing) the LD 50 was 2.5 Gy (250 rad). There have been few documented cases of survival beyond 6 Gy.
Significant gamma-ray emission from our galaxy was first detected in 1967 [9] by the detector aboard the OSO 3 satellite. It detected 621 events attributable to cosmic gamma rays. However, the field of gamma-ray astronomy took great leaps forward with the SAS-2 (1972) and the Cos-B (1975–1982) satellites. These two satellites provided an ...
Such interactions generate an afterglow in X-ray frequencies, usually seen as concentric rings of scattered X-rays with the gamma ray burst at the center. GRB 221009A is only the seventh gamma-ray burst known to have generated these rings, [ 10 ] and as of March 2023, a record twenty X-ray afterglow rings had been identified around the burst ...
Gamma radiation detected in an isopropanol cloud chamber. Gamma (γ) radiation consists of photons with a wavelength less than 3 × 10 −11 m (greater than 10 19 Hz and 41.4 keV). [4] Gamma radiation emission is a nuclear process that occurs to rid an unstable nucleus of excess energy after most nuclear reactions. Both alpha and beta particles ...