Detection of polarized ultraviolet emission from the high-redshift radio galaxy 3C 265

We have detected significant polarization of the UV emission from the high-redshift radio galaxy 3C 265. The nucleus is 9.2% (±2.2%) and 8.4% (±2.1%) polarized at B and R, respectively. The position angle of the electric field of the observed radiation is perpendicular to the axis of the radio emission and to the major axis of the UV emission of the galaxy in both passbands. The observed high level of polarization suggests that a substantial fraction of the UV emission is either scattered or produced by a nonthermal source. For 3C 265, we can place an upper limit of 13% (2 σ) for the polarization of the integrated extended emission.