释义 |
active galactic nucleus
active galactic nucleusn. A galactic nucleus that emits more radiation than can be accounted for solely by light from the stars it contains.active galactic nucleus
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. See AGN See AGN |