Density maps of disk stars illustrating the global morphological transformation of a galactic disk subject to bombardment by dark matter substructures. Brighter colors indicate regions of higher density of disk stars. The left panel shows the initial disk, while the right panel depicts the final disk after the violent gravitational encounters with the orbiting substructures. The edge-on (upper panels) and face-on (bottom panels) views of the disk are displayed in each frame.
Credit: Stelios Kazantzidis, Ohio State University