Active galactic nucleus

Active galactic nucleus

Compact region at a galaxy's center with abnormally high luminosity

BL Lacertae object

Active galactic nucleus with rapid and large-amplitude flux variability and significant optical polarization and with spectrum dominated by a featureless nonthermal emission continuum

Blazar

Very compact quasi-stellar radio source

Eddington luminosity

Maximum luminosity of a body in hydrostatic equilibrium

Low-ionization nuclear emission-line region

Type of galactic nucleus

Luminous infrared galaxy

Galaxy with a high luminosity

Lyman-alpha forest

Astronomical spectroscopic term

Quasar

Active galactic nucleus containing a supermassive black hole

Radio galaxy

Type of active galaxy that is very luminous at radio wavelengths

Seyfert galaxy

A class of active galaxies with very bright nuclei