active galactic nucleus or active galaxy nuclei

English - English

Definition of active galactic nucleus or active galaxy nuclei in English English dictionary

AGN

Related Terms

active galactic nucleus

Small region at the centre of a galaxy that emits a prodigious amount of energy in the form of radio, optical, X-ray, or gamma radiation or high-speed particle jets. Many classes of "active galaxies" have been identified; they appear similar in many respects to quasars. Astronomers suspect that the observed energy is generated as matter accretes onto a supermassive black hole with a mass millions or even billions of times that of the Sun. The accreting matter can outshine the rest of the galaxy as it is heated in very high-speed collisions outside the black hole's event horizon. It is believed that many galaxies harbour these central black holes and that they might have been quasars in their early history, although they now appear to be dormant unless orbiting matter is accreting onto the black hole

Hyphenation

ac·tive ga·lac·tic nu·cle·us or ac·tive gal·a·xy nu·cle·i

Turkish pronunciation

äktîv gıläktîk nukliıs ır äktîv gälıksi nukliay

Pronunciation

/ˈaktəv gəˈlaktək ˈno͞oklēəs ər ˈaktəv ˈgaləksē ˈno͞oklēˌī/ /ˈæktɪv ɡəˈlæktɪk ˈnuːkliːəs ɜr ˈæktɪv ˈɡæləksiː ˈnuːkliːˌaɪ/