Detail of the two linear fits (transparent straight lines) before and after the truncation radius. These lines fit the RSBPs extracted at 3, 3.5, and 4 kpc above and below the galaxy mid-plane (columns) for each ultra-deep g (blue), r (green), and i (red) band (rows). The surface brightness profiles are those from the PSF-deconvolved models of NGC 4565 shown in Figs. A.5–A.7. In each panel, the intersection radius between the two lines provides the truncation radius of the corresponding profile, which is indicated with a dashed vertical line. The truncation radius value is indicated in the top-right corner.