NED object is Centaurus A; Reference is  1983ApJ...273..128B

   Fig. 2. - Overlay of the 6 cm hybrid D-configuration radio contour map of
 Cen A onto a B-band optical photograph of NGC 5128. The radio clean beam is
 15.6 arcsec x 10.1 arcsec, PA = +16.2deg. The contours are -1, 1, 2, 4, 8, 16,
 32, and 64 per cent of the peak, 6.45 Jy per beam. The optical photograph,
 kindly provided by John Graham, was taken with the CTIO 4 m telescope (see
 Graham 1979 and references therein).