active galactic nucleus

(redirected from Active Galaxy Nuclei)
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active galactic nucleus

(AGN) See active galaxy.

active galactic nucleus

[¦ak·tiv gə‚lak·tik ′nü·klē·əs]
(astronomy)
A central region of a galaxy, a light-year or less in diameter, where violent and apparently explosive behavior is observed which is manifested in many ways, including the high-velocity outflow of gas, strong nonthermal radio emission, intense and often polarized and highly variable radiation over a wide range of wavelength bands, and ejection of jets of relativistic material.
References in periodicals archive ?
It carried four instruments: the BATSE gamma-ray burst detector, which disproved earlier theories that these energetic blasts come from our own galaxy; the OSSE and Comptel medium-energy gamma-ray telescopes, which studied emissions in the Milky Way and from nearby active galaxy nuclei; and the EGRET high-energy detector, which discovered a range of new sources, including gamma-ray quasars.