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Published online by Cambridge University Press: 12 April 2016
We discuss kinematical evidence that highly ionized (‘coronal’) lines are emitted from gas sharing the same velocity field as the BLR, NLR, and extended NLR. A close correlation between ionization potential and line width and blueshift with respect to systemic velocity suggests a hot outflow being responsible for the emission of coronal lines. This outflow is probably connected to the warm absorber observed in X-rays and the outflowing radio plasma. The high degree of ionization is dominantly due to photons from the blue bump but contributions from shocks are indicated in at least some of the sources observed.