Cosmic Rays from Cygnus X-3

For a long time, the origin of cosmic radiation has represented a challenge to the imagination of astrophysicists. This radiation, which was discovered in 1912, is raining down on the earth from all directions at a uniform rate. Now, however, a major source of cosmic radiation has finally been found in an object called Cygnus X-3. This object is the third- brightest X-ray emitter in the constellation Cygnus. It was first observed by X-ray astronomers in the late 1960s. Recently, it was found that Cygnus X-3 is also the source of high-energy gamma rays. On the basis of the observed gamma rays the object was identified as a source of cosmic radiation. Cygnus X-3 is a binary star system located at a distance of at least 37,000 light years at the edge of the Galaxy. Attention is given to models of Cygnus X-3, mechanisms involved in the production of cosmic rays, problems regarding the identification of the sources of cosmic rays, studies of Cygnus X-3, and details regarding cosmic rays. (G.R.)