Disk galaxy

A disc galaxy is a galaxy characterized by a disc, a flattened circular volume of stars. These galaxies may or may not include a central non-disc-like region (a galactic bulge).

Junko Ueda observed that galaxy collisions result in disc galaxies, within 40 million light years from the universe. While the galaxies are interacting, they change shape in cosmic time as they merge.

Disc galaxy types include:

Galaxies that are not disc types include:

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