From optical spectropolarimetry of Cygnus A we conclude that the scattering medium in the ionization cones in Cygnus A is moving outward at a speed of 170 \pm 34 km s ^ { -1 } , and that the required momentum can be supplied by the radiation pressure of an average quasar .
Such a process could produce a structure resembling the observed ionization cones , which are thought to result from shadowing by a circumnuclear dust torus .
We detect a polarized red wing in the [ O III ] emission lines arising from the central kiloparsec of Cygnus A .
This wing is consistent with line emission created close to the boundary of the broad-line region .