Optical/UV/X-ray Insights into the RL--RQ Dichotomy

摘要

We explore the relationship between radio-loud (RL) and radio-quiet (RQ)quasars using a set of optical/UV/X-ray measures that are quite independent ofradio measures. We find RL sources to show larger average FWHM H-beta, weakerFeII emission, no soft X-ray excess and no CIV blueshift - all characteristicsmanifested by a large fraction of RQ quasars (that we call Population A). Wefind that log L (1.4Ghz) = 31.6 [ergs/s/Hz] (or R=70) is the lower limit for RLquasars showing FRII morphology. We find no evidence for a hidden FRIIpopulation below this level. We conclude that RL sources are a distinct quasarpopulation that may also include 30-40 percent of RQ sources which apparentlyshow similar geometry and kinematics (what we call Population B). This RQoverlap, if not coincidental, may include inactive RL quasars as well asquasars with geometry/kinematics similar to RL sources but where RL activity isinhibited in some way (e.g. host morphology, BH spin).