An Etymological Dictionary of Astronomy and Astrophysics

A self-gravitating entity which has been formed from tidal material expelled during interactions between larger galaxies. TDGs are typically found at the tip of tidal tails at distances between 20 and 100 kpc from the merging galaxies, of which at least one should be a gas-rich galaxy. They are gas-rich objects that can be as massive as the Magellanic Clouds, form stars at a rate which might be as high as
in blue compact dwarf galaxies and seem dynamically independent from their parent galaxies.

See also: → tidal; → dwarf;
→ galaxy.