What Types of Jets Does Nature Make? A New Population of Blazars

We have recently discovered a population of strong-lined blazars with jet synchrotron emission peaks in the UV/X-ray regime. So far, only radio quasars with lower synchrotron energy cut-offs (and so X-rays dominated by inverse Compton emission) were known. Our discovery challenges theories which posit that particle cooling by an external radiation field, such as the one produced by, e.g., an accretion disk, controls the jet synchrotron spectral cut-off. Here we present the first VLA maps and preliminary results from XMM spectroscopy of these new class of blazars and discuss their relation to the high-energy peaked BL Lacertae objects. H.L. acknowledges financial support from the Deutsche Akademie der Naturforscher Leopoldina.