Lecture 26 - Radio Galaxies
Radio emission from an external galaxy was first detected around 1950 from the powerful galaxy Cygnus A. There was a suggestion that it was a `double radio source'. This discovery catalyzed the quest for achieving higher angular resolution. This led to the discovery of "Aperture Synthesis" telescopes. Sir Martin Ryle in Cambridge was awarded the Nobel Prize for this discovery. Observations with high angular resolution revealed a remarkable morphology of `Radio Galaxies'. There was a compact central source, presumed to be a super-massive black hole. There were two relativistic jets of particles emanating from the central source, and two gigantic 'lobes' of radio emission at both ends of the jet. This lecture is intended to be an introduction to the world of giant radio galaxies.