Radio galaxies can also be classified as giant radio galaxies (GRGs), whose radio emissions can extend to scales of megaparsecs (3.26 million light-years). Alcyoneus is an FR II class low-excitation radio galaxy which has the largest observed radio emission, with lobed structures spanning 5 megaparsecs (16×106 ly). For comparison, another similarly sized giant radio galaxy is 3C 236, with lobes 15 million light-years across. It should however be noted that radio emissions are not always considered part of the main galaxy itself.
radio galaxies can also be classified as giant radio galaxies (grgs) whose radio emissions can extend to scales of megaparsecs (326 million light-years) alcyoneus is an fr ii class low-excitation radio galaxy which has the largest observed radio emission with lobed structures spanning 5 megaparsecs (16×106 ly) for comparison another similarly sized giant radio galaxy is 3c 236 with lobes 15 million light-years across it should however be noted that radio emissions are not always considered part of the main galaxy itself