Radio Galaxies
Many galaxies are strong radio emitters, called radio galaxies. Some of the more notable are Centaurus A and Messier 87.
Quasars (short for "quasi-stellar radio source") were one of the first point-like radio sources to be discovered. Quasars' extreme red shift led us to conclude that they are distant active galactic nuclei. Active galactic nuclei have jets of charged particles which emit synchrotron radiation. One example is 3C 273, the optically brightest quasar in the sky.
Merging galaxy clusters often show diffuse radio emission.
Read more about this topic: Astronomical Radio Source
Famous quotes containing the words radio and/or galaxies:
“All radio is dead. Which means that these tape recordings I’m making are for the sake of future history. If any.”
—Barré Lyndon (1896–1972)
“Don’t you see what’s at stake here? The ultimate aim of all science—to penetrate the unknown. Do you realize we know less about the earth we live on than about the stars and the galaxies of outer space? The greatest mystery is right here, right under our feet.”
—Walter Reisch (1903–1963)