extragalactic astronomy
(astronomy of other galaxies, galaxy clusters, AGNs, quasars, etc.)
The term extragalactic astronomy is astronomy beyond the Milky Way:
such as other galaxies, galaxy clusters, quasars, and active galactic nuclei.
(science,astronomy,galaxies,AGN,quasars)
Further reading:
http://en.wikipedia.org/wiki/Extragalactic_astronomy
Index