Disc galaxy

The Sculptor Galaxy (NGC 253) is a 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 Earth. While the galaxies are interacting, they change shape in cosmic time as they merge.^[1]

Disc galaxy types include:

• spiral galaxies
  • unbarred spiral galaxies (types S, SA)
  • barred spiral galaxies (type SB)
  • intermediate spiral galaxies (type SAB)
• lenticular galaxies (types E8, S0, SA0, SB0, SAB0)

Galaxies that are not disc types include:

• elliptical galaxies (type dE)
• irregular galaxies (type dI)

References