Astroparticle Physics

314 16 GlossaryExtragalactic gamma-ray sources flaring up only once. Spectacu-lar supernova explosions (hypernova) or colliding neutron stars arepossible candidates for producing gamma-ray bursts.gamma astronomygamma burstergamma raysgeneral principle of relativitygeneral relativitygeneral theory of relativitygenerationGLASTgluinogluongrand unificationgravitational collapsegravitational instabilityAstronomy in the gamma energy range (> 0.1MeV).Short-wavelength electromagnetic radiation corresponding to en-ergies ≥ 0.1MeV.The principle of relativity argues that accelerated motion and beingexposed to acceleration by a graviational field is equivalent.Einstein’s general formulation of gravity which shows that spaceand time communicate the gravitational force through their curvature.Generalization of Newton’s theory of gravity to systems with rela-tive acceleration with respect to each other. In this theory gravitationalmass (caused by gravitation) and inertial mass (mass resistingacceleration) are equivalent.A set of two quarks and two leptons which form a family. Theorder parameter for families is the mass of the family members.The first generation (family) contains the up and down quark, theelectron and the electron neutrino. The second generation containsthe charm and strange quark as well as the muon and its associatedneutrino. The third generation comprises the top and bottom quarkand the tau with its neutrino.Gamma-ray Large Area Space Telescope. GLAST will measure γrays in the energy range 10 keV–300 GeV. The space experiment isexpected to be launched in 2005.Supersymmetric partner of the gluon.g; the gluon is the carrier of strong interactions. There are alto-gether eight different gluons, which differ from each other by theircolour quantum numbers.A theory which combines the strong, electromagnetic, and weakinteractions into one unified theory (GUT).If the gas and radiation pressure of a star can no longer resist the in-wardly directed gravitational pressure, the star will collapse underits own gravity.Process by which density fluctuations of a certain size grow byself-gravitation.