Article
The Circinus Galaxy, a Type II Seyfert galaxy
Seyfert galaxies are one of the two largest groups of active galaxies, along with quasar host galaxies. They have quasar-like nuclei (very luminous sources of electromagnetic radiation that are outside of our own galaxy) with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, their host galaxies are clearly detectable.