When two spiral galaxies collide, the hydrogen present on their disks is compressed producing strong star formation as can be seen on interacting systems like the Antennae Galaxies.

Two very prominent examples of collisions producing tidal tails are the Mice Galaxies and the Antennae Galaxies.

Examples of these formations can be seen in NGC 4676 or the Antennae Galaxies.

Observations and simulations of colliding galaxies suggest that the Antennae Galaxies will eventually form an elliptical galaxy.

Rich deposits of neon, magnesium, and silicon were discovered from the Chandra X-ray Observatory analysis of the Antennae Galaxies.

Astronomy Picture of the Day: The Antennae Galaxies (10/22/1997)

Tidal forces can eject a significant amount of a galaxy's gas into the tail; within the Antennae Galaxies, for example, nearly half of the observed gaseous matter is found within the tail structures.

Some interacting galaxy pairs have two distinct tails, as is the case for the Antennae Galaxies, while other systems have only one tail.

The group's best known galaxies are the Antennae Galaxies (NGC 4038/NGC4039), a well-known interacting pair of galaxies.

The target of the observation was a pair of colliding galaxies with dramatically distorted shapes, known as the Antennae Galaxies.