Radio Jets

• Pioneering work by Pawsey & Bolton (Australia) and Ryle (Cambridge) found a number of sources of radio emission outside the Milky Way (or at least away from the galactic plane).

• Higher resolution imaging found:
  • sources are mostly associated with giant elliptical galaxies.
  • sources have a characteristic double structure.

• Still higher resolution imaging (interferometry) revealed that the double structure consists of well-collimated jets ending in diffuse lobes.
  • See, for example, this combined radio and optical image of 3C219.