2006ApJ...637..183L

We present the first deep VLA radio images of flat-spectrum radio quasars (FSRQs) with multiwavelength emission properties similar to those of BL Lacertae (BL Lac) objects with synchrotron X-rays. Our observations of 25 of these sources show that their radio morphologies are similar to those of other radio quasars. However, their range of extended powers is more similar to that of BL Lac objects and extends down to the low values typical of FR I radio galaxies. Five out of our nine lobe-dominated sources have extended radio powers in the range typical of both FR I and FR II radio galaxies, but their extended radio structure is clearly FR II-like. Therefore, we have not yet found a large population of radio quasars hosted by FR I galaxies. Two-thirds of our sources have a core-dominated radio morphology and thus X-rays likely dominated by the jet. We find that their ratios of radio core to total X-ray luminosity are low and in the regime indicative of synchrotron X-rays. This result shows that also blazars with strong emission lines can produce jets of high-energy synchrotron emission, and it undermines at least in part the ``blazar sequence'' scenario, which advocates the position that particle Compton cooling by an external radiation field governs the frequency of the synchrotron emission peak.