Active galactic nucleus feedback

Active galactic nucleus feedback is the transfer of energy and matter from a galaxy’s accreting central supermassive black hole into surrounding gas. It can regulate star formation and alter the growth of the galaxy and black hole.

Relativistic jet: A narrow outflow of plasma moving at speeds close to the speed of light, launched from an active galactic nucleus. Jets carry black-hole energy across galaxies and can deposit it far from the nucleus.
Galaxy quenching: The cessation or strong reduction of star formation in a galaxy. Removing or heating cold gas can help shut down star formation.
X-ray cavities: Depressions in the X-ray-emitting gas of galaxy clusters, often inflated by active-galactic-nucleus jets. Their size and pressure help estimate energy injected by radio jets.
Stellar feedback: The influence of energy and matter released by stars and their remnants on surrounding gas. It also regulates star formation, but originates from stellar processes rather than the central black hole.
Active galactic nucleus wind: A large-scale outflow of gas driven from the central regions of an active galaxy. Winds transfer momentum and energy into gas surrounding the black hole.
M-sigma relation: An observed correlation between a galaxy’s central black-hole mass and the velocity dispersion of its stars. Feedback is one proposed explanation for the connection between black-hole and galaxy growth.
Radio lobes: Extended regions of radio-emitting plasma formed as jets inflate bubbles beyond a galaxy’s nucleus. Lobes reveal where jet energy has been transported and deposited.
Supernova feedback: The effects of supernova explosions on the gas, dust, and star formation in a galaxy. Supernovae provide a competing source of energy, especially in low-mass galaxies.
Radiative feedback: The influence of emitted radiation on the temperature, ionization, and motion of nearby matter. Radiation from the accretion flow can heat or push gas without a jet.
Circumgalactic medium: The diffuse gas surrounding a galaxy, extending beyond its visible stellar body. Outflows and jets deposit energy and metals into this gas reservoir.

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