NED object is 3C 031; Reference is 1979MNRAS.187..187B

   Figure 4. Lines representing the percentage polarizations and position
 angles of the electric vectors at 1.4 and 2.7 GHz. The vectors at 2.7 GHz are
 represented by the thinner lines and several contours from the I map at 1.4
 GHz (Fig. 1 ) are also shown. The vertical line indicates the length scale of
 the vectors.