A catalogue of quasars and active nuclei: 11th edition

The recent release of the final installement of the 2dF quasar catalogue and of the first part of the Sloan catalogue, almost doubling the number of known QSOs, led us to prepare an updated version of our Catalogue of quasars and active nuclei which now contains 48 921 quasars, 876 BL Lac objects and 15 069 active galaxies ( including 11 777 Seyfert 1s). Like the tenth edition, it includes position and redshift as well as photometry ( U, B, V) and 6 and 11 cm flux densities when available. We also give a list of all known lensed and double quasars.