Optical images of the central region of NGC 1316 (left panel) and NGC 612 (right panel) in inverted gray scale and overlaid contours of the radio emission in yellow. The size of the images is 2′ × 2′ and the bright extended radio lobes are located outside the pictures. The rectangles show the regions from which the Spitzer IRS spectra displayed in Fig. 3 were extracted. For NGC 1316, the size of the rectangle is with a position angle (PA) of 149°. For NGC 612, it is with a PA of . Left panel: HST image of NGC 1316 with 4.9 GHz radio contours of the inner jet overlaid (Geldzahler & Fomalont 1984). The radio contours increase by a factor of 2 from 0.2 to 3.2 mJy/beam, where the beam is , with a PA of . Right panel: digitized Sky Survey image of NGC 612. The 6 cm radio contours are 5, 10 and 20 mJy/beam and the beam is with a PA of (a larger radio continuum image of NGC 612 can be seen in Fig. 6 of Emonts et al. 2008). Note that NGC 612 is about six times more distant than NGC 1316.