article_snippet: A radio galaxy is an active galaxy that is very luminous at radio wavelengths.
article_snippet: A radio galaxy is usually composed of two jets being expelled from a large elliptical galaxy.
article_snippet: Radio galaxies can be detected at large distances, which makes then useful tools in studying the structure of the universe.
article_snippet: Star formation in such galaxies is a strong source of radio waves, which come from supernova remnants and cosmic rays that are energised in the star formation regions.
article_snippet: There is also a handful of objects known as radio galaxies, which each have a massive central black hole that emits jets of plasma.