Amazing Universe: Origin, Evolution And Quasar Controversy:- Obini Ekpe E

ABSTRACT

The sky is very beautiful. Some ofthe objects m the sky are ordinary stars. Others merely look like stars. Yet, others are huge collections ofstars called galaxies (Plate 2). Majority ofthese objects have optical as well as radio emissions. Ifthe radio emission ofa galaxy is much greaterthan that ofa normal galaxy, that galaxy is called a radio galaxy. Radio contour maps show that most radio galaxies consist oftwo large clouds ofradio emission symmetrically disposed on either side ofthe main galaxy. The luminosities of these galaxies span a range from 1031 Js'1 (for normal galaxies) to 1038Js-1 (for sources like 3C 295 and Cygnus A). Radio galaxies are only a class ofradio sources. Other sources include seyferts, LINER galaxies, quasi-stellar objects, BL Lac objects and quasars (Ekpe, 2005d). Quasars are a very controversial class of radio sources (Ekpe, 2005).