Astrophysics (Index)About

gamma-ray burst

(short flashes of gamma rays apparently from outside our galaxy)

A gamma-ray burst (GRB) is a short flash of gamma rays, lasting from a few milliseconds to several minutes, often followed by an afterglow (GRB afterglow) of longer-wavelength radiation. Roughly half are accompanied by a visible transient (GRB optical transient), the others being termed dark bursts. Some show such extreme energy that it is presumed that the source emits them directionally, i.e., they cannot be from an isotropic emission. GRBs were first detected in 1967 by satellites intended to detect nuclear weapons tests. A significant part of gamma-ray astronomy is detection and study of the bursts, and gamma ray observatory satellites have invariably included burst detectors. Presumed sources (GRB progenitors, gamma-ray burst progenitors) include supernovae, magnetars, and/or mergers of neutron stars. The latter is theorized as a cause of short gamma ray bursts (SGRB), i.e., those lasting less than two seconds. Superluminous supernovae are theorized to create long gamma ray bursts (LGRB), i.e., more than two seconds. Thus GRB light curves are part of their study. The term GBS for gamma-ray burst source or gamma burst source used for bodies such as pulsars presumed to be sources. Some bursts have been termed FRED GRBs for fast rise exponential decay GRBs.

An orphan afterglow (orphan GRB afterglow) is the appearance of an afterglow not subsequent to an apparent GRB. The presumption is that the GRB gamma rays are highly beamed but the afterglow spreads a bit wider, so we can observe the afterglow of some GRBs that miss us.

(EMR,gamma rays,event type,transient type)
Further reading:
GBSGBS 0525-66or GRB, "gamma burst source"
GRBGRB 170817Ageneral GRB prefix

Referenced by pages:
Compton Gamma Ray Observatory (CGRO)
Compton telescope
Fermi (FGST)
Fenton Hill Observatory (FHO)
gamma rays (GR)
habitable zone (HZ)
high-B radio pulsar (HBRP)
high-energy astrophysics (HEA)
Hercules-Corona Borealis Great Wall (Her-CrB GW)
High Energy Transient Explorer (HETE)
hypermassive neutron star (HMNS)
International Cometary Explorer (ICE)
Livermore Optical Transient Imaging System (LOTIS)
mass extinction
MASTER Robotic Net
multi-messenger astronomy
Pi of the Sky
Pioneer Venus Orbiter (PVO)
soft gamma repeater (SGR)
superluminous supernova (SLSN)
Transiting Exoplanet Survey Satellite (TESS)
transient astronomy
X-ray burster (XRB)