An Emission Line Galaxy (ELG) is a class of galaxies characterized by the presence of Emission Lines. The label is used for distant galaxies (i.e., with significant Redshift) that fit the description. Other classifications are Absorption Line Galaxies and A+E Galaxies (featuring both).

Some typical emission lines are:

• [O II] (372.7nm)
• H-δ (410.2nm, Balmer Series)