THE LOCAL LUMINOSITY FUNCTION OF QSOS AND SEYFERT-1 NUCLEI

We present the analysis of a new flux-limited sample of bright quasars and Seyfert 1 galaxies in an effective area of 611 deg(2), drawn from the Hamburg/ESO survey. We confirm recent claims that bright quasars have a higher surface density than previously thought. Special care wa s taken to avoid morphological and photometric biases against low-reds hift quasars, and about 50 % of the sample objects are at z < 0.3, spa nning a range of Delta M similar or equal to 8 in absolute magnitudes. While our derived space densities for low-luminosity Seyfert 1 nuclei are consistent with those found in the literature, we find that lumin ous QSOs, M-B < -24, are much more numerous in the local universe than previous surveys indicated. The optical luminosity functions of Seyfe rt 1 nuclei and QSOs join smoothly, and if the host galaxy contributio ns are taken into account, a single power-law of slope alpha = -2.2 de scribes the combined local luminosity function adequately, over the fu ll range in absolute magnitude. Comparing our data with published resu lts at higher redshifts, we can rule out pure luminosity evolution as an acceptable parametrisation; the luminosity function of quasars chan ges shape and slope with z, in the sense that the most luminous quasar s show the weakest evolution.