One more sample supporting the cosmological evolution of flat-spectrum quasars.

A complete sample of quasars has been drawn from the NRAO-MPI 5 GHz surveys and the Parkes 2.7 GHz surveys. The area covered is 9.811 sr of the sky, the largest possible one. The luminosity-volume (V/V_m) test applied to this sample shows strong cosmological evolution for all quasars, both steep and flat-spectrum sources. There is no statistically significant difference, in the resulting values of <V/V_m>, between these two types of objects. The conclusion does not depend on the world model used: the V/V_max test leads to quasar evolution also in models with non-zero cosmological constant.