Spectrophotometric Investigation of a Sample of Tidal Dwarf Galaxies

We define a Tidal Dwarf Galaxy (TDG) as a self-gravitating entity of dwarf-galaxy mass built from tidal material expelled during interactions. We then summarize our findings on broad-band imaging and spectroscopy of a sample of TDG candidates in a sequence of interacting systems. Evidence for decoupled kinematics in the ionized gas have been found in several objects. This could indicate that they are bound galaxies and therefore genuine TDGs. As a detailed example we analyze the system AM 1159-530, where surprisingly high velocity gradients have been measured.