Radio Galaxies and Quasars, II

Abstract

It is my pleasant duty and high privilege to continue the story of radio galaxies and quasars begun by Professor Ryle. Because the intenseness of activity has been so great, and the advance of knowledge so remarkably rapid in this field, it is surprising to recall that only 9 quasars were known at the time of the Hamburg meeting of the Union just 3 years ago. Several hundred are now known, and techniques exist for the discovery of thousands more at will. At the time of Hamburg, less than a year had passed since M. Schmidt’s discovery of the red-shift in 3C 273. Hoffleit and Smith, and Matthews and myself had only just established the optical variation of 3C 273 and 3C 48, respectively. There was no knowledge of how extensive the phenomenon of optical variability was, nor of the exceedingly short time-scales of the variation. Ideas of the number of quasars, radio and non-radio, were not yet formed, and the feature of radio doubling had not yet been established as a general characteristic.