NED object is NGC 1052; Reference is  1984ApJ...284..531W

   Fig. 2.- (b) A CLEANed map of the linearly polarized intensity at 1.66 GHz
 of the nucleus of NGC 1052, restored with the same beam as shown in Fig. 1a.
 The peak signal is 1.39 mJy per beam, the contour interval is 135 {mu}Jy per
 beam (rms noise level), and contours at 5, 6, 7, 8, 10, 12, and 14 times this
 interval are shown. Most or all of the peak signal is probably instrumental
 in origin (see text). Away from the peak, the contours show the
 signal-to-noise for features brighter than or equal to 5 times the noise
 level.