出典:Wikipedia
出典:『Wikipedia』 (2011/07/10 17:23 UTC 版)
Cygnus A (3C 405) is one of the most famous radio galaxies, and among the strongest radio sources in the sky. It was discovered by Grote Reber in 1939. In 1951, Cygnus A, along with Cassiopeia A, and Puppis A were the first "radio stars" identified with an optical source, of these, Cygnus A became the first radio galaxy; the other two being nebulae inside the Milky Way. In 1953 Roger Jennison and M K Das Gupta showed it to be a double source. Like all radio galaxies, it contains an active galactic nucleus.