A Blazar is a very compact Quasar (QSO) in an Active Galactic Nucleus (AGN). They are thought to be powered by material falling into a Supermassive Black Hole (SMBH) and are thought to beam their Electromagnetic Radiation (EMR) to make them especially bright despite their distance. The name blazar was given to objects that are both BL Lac Objects (objects similar to the Active Galaxy BL Lacertae) and OVV Quasars (Optically Violent Variable Quasars).
Cosmic Gamma Ray Background (CGB)
Radio Galaxy (RG)