Contour map of the total power emission of the Leo Triplet at 2.64 GHz. Superimposed are the apparent B-vectors of polarised intensity overlaid upon the blue image from DSS. The contour levels are 3, 5, 10, 20, 50, and 100 × 1.0   mJy/beam. A polarisation vector of 1′ corresponds to a polarised intensity of 1 mJy/beam. The beam size is . The rectangular frame represents the area covered by Fig. 3.