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

摘要

We explore the relationship between radio-loud (RL) and radio-quiet (R.Q) quasars using a set of optical/UV/X-ray measures that are quite independent of radio measures. We find RL sources to show larger average FWHM Hβweaker Fell emission, no soft X-ray excess and no CIV blueshift all characteristics manifested by a large fraction of RQ quasars (that we call Population A). We find that log L_(1.4Gh)z =31.6 ergs s~(-1) Hz~(-I) (or R=70) is the lower limit for RL quasars showing FRII morphology. We find no evidence for a hidden FRII population below this level. We conclude that RL sources are a distinct quasar opulation that may also include 30-40% of RQ sources which apparently show similar geometry and kinematics (what we call Population B). This RQ overlap, if not coincidental, may include inactive RL quasars as well as quasars with geometry/kinematics similar to RL sources but where RL activity is inhibited in some way (e.g. host morphology, BH spin).