Astroparticle Physics

16 Glossary 329The metric describing an isotropic and homogeneous space-time ofthe universe.German–British–American Roentgen satellite (launched 1990).Quantum number which distinguishes supersymmetric particlesfrom normal particles.Soviet–American Gallium Experiment for the measurement of solarneutrinos from the pp cycle.Necessary conditions first formulated by Sakharov which are requiredto create a matter-dominated universe: a baryon-numberviolatingprocess, violation of C or CP symmetry, and departurefrom thermal equilibrium.Small Astronomy Satellite; gamma-ray satellites launched byNASA, 1972 (SAS-2) resp. 1975 (SAS-3).The scale factor denotes an arbitrary distance which can be usedto describe the expansion of the universe. The ratio of scale factorsbetween two different epochs indicates by how much the size ofthe universe has grown.Event horizon of a spherical black hole, R = 2GM/c 2 .Excitation of atoms and molecules by the energy loss of chargedparticles with subsequent light emission.Secondary cosmic rays are a complex mixture of elementary particles,which are produced in interactions of primary cosmic rayswith the atomic nuclei of the atmosphere.Supersymmetric partner of the electron.Member of a small class of galaxies with brilliant nuclei and inconspicuousspiral arms. Seyfert galaxies are strong emitters in theinfrared and are also detectable as radio and X-ray sources. Thenuclei of Seyfert galaxies possess many features of quasars.Soft Gamma-Ray Repeaters are objects with repeated emission ofγ bursts. Presumably soft gamma-ray repeaters are neutron starswith extraordinary strong magnetic fields (see magnetar).A sudden pressure, density, and temperature gradient.Robertson–Walker MetricROSATR paritySSAGE experimentSakharov conditionsSAS-2, SAS-3scale factorSchwarzschild radiusscintillationsecondary cosmic raysselectronSeyfert galaxySGR objectsshock front