Notes. The complete table is published in its entirety at the CDS. A portion is shown here for guidance regarding its form and content. In the first part, we list the X-ray detected AGN; in the second part, we report basic data for the 11 sources in the “control sample” undetected in the X-ray (see text).Column (1): unique source identification number in the 2XMMi catalogue; for the X-ray undetected sources, arbitrary ID number. Columns (2) and (3): J2000 right ascension and declination of the X-ray object (in degree). Column (4): XMM-Newton EPIC-pn flux between 0.2 and 12 keV (entry xmm_pn_8_flux in the 2XMMi catalogue), in units of 10^-14 ergs cm^-2 s^-1; for the X-ray undetected sources, XMM-Newton EPIC upper limit to the flux from FLIX. Column (5): redshift for the SDSS counterpart. Column (6): unique spectroscopic ID in the SDSS catalogue. Columns (7) and (8): J2000 right ascension and declination of the optical object (in degree). Columns (9)−(11): magnitudes in the g, r, and i SDSS filters. Column (12): standard deviation of the Gaussian fitted to the Mg ii line (in Å). Column (13): continuum value below the Mg ii line (in units of 10^-17 ergs cm^-2 s^-1 Å^-1). Column (14): integrated radio flux density at 1.5 GHz (observed frame; in units of mJy), from the FIRST survey; OutFIRST: source not covered by FIRST; undet.: source covered but not detected by FIRST.