Discovery of a high-speed outflow in 4C 74.26

We present intermediate-resolution optical spectropolarimetry of the radio- loud quasar 4C 74.26. Large variations in both the degree and position angl e of polarization are observed across the broad H alpha line. After continu um subtraction, we find that in polarized Aux this feature is redshifted by approximate to 2000 km s(-1) relative to its median wavelength in total fl ux. We show that the H alpha polarization can be explained by scattering in a high-speed outflow which, if it is directed along the axis of the radio jet, must have a velocity greater than or similar to 5000 km s(-1) in order to account for the observed redshift. The polarization position angle is n ot precisely orthogonal to that of the radio source, suggesting that the sc attering outflow is either inhomogeneous, or somewhat misaligned with the j et axis.