active galactic nucleus

American  

[ak-tiv-guh-lak-tik noo-klee-uhs, nyoo-klee-uhs] / ˈæk tɪv gəˈlæk tɪk ˈnu kli əs, ˈnyu kli əs /

noun

1. Astronomy. a large, extremely bright region at the center of a galaxy, its brightness thought to come from the huge amounts of radiant energy emitted by dust particles and gases falling into a massive black hole within the region.

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active galactic nucleus Scientific  

/ ăk′tĭv /

1. See under galactic nucleus

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Example Sentences

The steep rise in the spectrum that inspired the name The Cliff can be explained by a dense, spherical, turbulent gas envelope around an active galactic nucleus.

From Science Daily • Nov. 29, 2025

As the absorbing material consistently resides between the active galactic nucleus and Earth, this indicates that the team has successfully captured the accretion flow heading toward the active galactic nucleus.

From Science Daily • Nov. 6, 2023

A quasar is an active galactic nucleus that is believed to be energized by a supermassive black hole.

From Salon • Jul. 4, 2023

The second theory is that they result from the activities of an active galactic nucleus, with radio jets spewing particles to create the ORC’s shape.

From Scientific American • Mar. 29, 2022

How does the presence of an active galactic nucleus in a starburst galaxy affect the starburst process?

From Textbooks • Oct. 13, 2016