If this happens that would increase the density at the center of a galaxy, and thus make a bulge that has properties similar to disk galaxies.

Thus if two disk galaxies collide, they begin with their stars in an orderly rotation in the plane of the disk.

Freeman Law is a statement in astronomy which says that disk galaxies have a constant surface brightness, Σ.

Lenticular and spiral galaxies, taken together, are often referred to as disk galaxies.

Two of the objects are edge-on disk galaxies with smaller companion galaxies nearby.

One of the main challenges to galaxy formation is the great number of thin disk galaxies in the local universe.

An image of an ongoing merger of equal sized disk galaxies is shown left.

Imagine looking at two disk galaxies edge-on, one with a bulge and one without a bulge.

Thus a sample of disk galaxies with prominent spheroidal components will have more galaxies at larger axial ratios.

These effects make kinematic measurements of lenticular galaxies considerably more difficult compared to normal disk galaxies.