Presentation #101.03 in the session “AGN I (Oral)”.
Radio-loud quasars (RLQs) are more X-ray luminous than predicted by the X-ray–optical/UV relation for radio-quiet quasars(RQQs). The excess X-ray emission depends on the properties of radio jets. We perform large-scale archival Chandra/XMM-Newton data mining to investigate the X-ray–optical/UV–radio relation of optically selected RLQs. Model selection using information criteria supports the scenario where the disk/corona instead of the jets dominate the X-ray emission, which challenges 35 years of thinking about the basic nature of the nuclear X-ray emission of RLQs. A distinct jet component is likely important for only a small portion of flat-spectrum radio quasars. The corona–jet, disc–corona, and disc–jet connections of RLQs are likely driven by independent physical processes. Furthermore, the corona–jet connection implies that small-scale processes in the vicinity of supermassive black holes, probably associated with the magnetic flux/topology instead of black hole spin, are controlling the radio-loudness of quasars. The X-ray spectral and variability properties and the αox-EW He II correlation for RLQs also support the idea that the X-ray emission of typical RLQs mainly arises from the disc/corona.