NGC 3923 is an example of a shell galaxy where the stars in its halo are arranged in layers.

The shell-like structures are thought to develop as a consequence of galactic cannibalism, when a larger galaxy ingests a smaller companion.

As the two centers approach, they initially oscillate about a common center, and this oscillation ripples outwards forming the shells of stars just as ripples on a pond spread when the surface is disturbed.

[2] Deep imaging also detected a stream extending from the core of NGC 3923 and a small elliptical galaxy on its axis, which is a probable progenitor of some of the shells.

[3] Based on the velocity dispersion of the globular clusters of NGC 3923 the mass of the supermassive black hole of the galaxy was estimated to be