The active galaxy Markarian 421 seen across the electromagnetic spectrum
The active galaxy Markarian 421 seen across the electromagnetic spectrum
The black hole plus accretion disk model for the center of an active galaxy
Examples of active galaxy variability
The optical spectrum of the quasar 3C 273
Composite radio (red) and optical (blue) image of the active galaxy 3C 219
The spectacular radio jet of the nearby active galaxy M87
