The optical luminosity function of Seyfert 1 nuclei

We have collected from the literature all confirmed Seyfert 1 and 1.5 galaxies in the area covered by the first nine Markarian lists and we have estimated their nuclear magnitudes in two independent ways. We have then defined a ‘homogeneous’ subsample suitable for deriving the luminosity function with the method described by Neyman & Scott. Our derivation incorporates corrections for incompleteness, for random errors in the nuclear magnitudes and for the effect of binning. The resulting luminosity function matches remarkably well that of optically selected QSOs at $$M_B\simeq-23 (H_0=50)$$, flattens out somewhat at $$M_B\simeq-21.5$$, but does not show clear evidence of a levelling off down to $$M_B\simeq-18;$$ it also compares favourably with the local luminosity function of X-ray-selected active galactic nuclei. Our results agree with those of previous investigations for $$M_B\gt-20$;$ at higher luminosities we differ from some recent estimates by factors of up to ten.