Here is an unsharp masked image of NGC 5128 taken from the paper (2002), Astronomical Journal, Volume 124, p.3144.
These shells are faintly visible in many images of NGC 5128, but in this artificially enhanced image, their contrast against the smooth background light of the elliptical component of this galaxy is magnified greatly.
NGC 5128 is what is known "in the trade" as a shell elliptical galaxy. As far as I know, it was Malin who first drew attention to these very-low contrast shells or ripples that can be found hiding in the smooth light of many elliptical galaxies.
These shells or ripples are believed to be the result of a lower mass galaxy merging with a big elliptical galaxy. In the case of N5128, the merger event that produced the dark lane also produced the ripples in the smooth light of the elliptical component.
The paper I have referred to is very interesting, in that it explains several very useful image processing techniques for extracting low contrast detail from the images of elliptical galaxies.
(just find the Astronomical Journal website using Google, and then click on the appropriate volume)
