Active Galactic Nuclei, Seyferts & Quasars: Physical Mechanisms

The central engine includes a supermassive black hole, accretion disk, hot corona, broad- and narrow-line gas, dusty structures, and in some systems relativistic jets. These regions occupy vastly different scales yet are dynamically linked.

Infalling gas releases gravitational energy efficiently as it spirals through an accretion disk. Intense radiation ionizes surrounding gas, while magnetic fields can launch jets. Orientation changes whether an observer sees the inner regions directly or through obscuring material.

Rapid variability limits the emitting-region size, broad spectral lines reveal fast gas near the nucleus, radio interferometry resolves jets, and stellar/gas dynamics confirm central supermassive black holes.

Gravitational energy released by accretion powers radiation; magnetic fields transport angular momentum and launch outflows. Orientation determines whether inner regions or jets dominate what an observer sees.