BL Lacertae Objects
Bright, starlike objects generally lacking any emission lines.
Low Ionization Nuclear Emission Regions (LINERs)
Very bright galactic nuclei showing emission lines from low ionization species
Very bright, starlike objects, usually showing extremely broad emission lines.
Galaxies whose emission is dominated by huge radio emitting regions outside the galax proper. Often jets are seen connecting the
nuclear regions of the galaxy to these lobes.
Spiral galaxies with very bright nuclei. These galaxies have strong emission lines, sometimes very broad, sometimes narrow.
The galaxies are usually disturbed looking. They do not have the bright nuclear regions of the objects listed above, buth they do show
evidence of extremely enhanced star formation, up to a hundred or even a thousand times that seen in normal spiral galaxies.