The Cosmic Evolution of Quasars

Abstract

Abstract.The form of the quasar luminosity function and its redshift dependence to z~l has long been established; powerful evolution is required so that by z = l there is an increase of order 10 2 -10 3 in the space density of the most luminous sources. However it is more difficult to deduce the form of the LF at high redshifts. In this contribution we discuss how a sample of relatively bright radio sources has been used to determine the high-redshift behavior of the radiodoud quasar luminosity function, and the particular advantages of using a radio-selected sample. Our results illustrate how radio-loud quasar samples can be an efficient probe of the high-redshift. Universe.