NED object is NGC 6146; Reference is  1984ApJ...287...41W

   Fig. 20.- NGC 6146 at 4.9 GHz. (b) Linearly polarized intensity. The peak is
 2.07 mJy beam **(-1), the CI is 0.10 mJy beam **(-1), and contours at 5, 6, 8,
 10, 12, 14, 16, 18, 20, and 22 times this CI are plotted.