galactic nucleus

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galactic nucleus

n.
The central region of a galaxy, containing a higher density of stars, dust, and gas than the rest of the galaxy and appearing brighter than the rest of the galaxy.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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References in periodicals archive
Galaxy IC 3639 obscured with active galactic nucleus Durham University
Speaking about it, Marius Cautun, study author and postdoctoral fellow at Durham University's Institute for Computational Cosmology, said in a statement, "The destruction of the Large Magellanic Cloud, as it is devoured by the Milky Way, will wreak havoc with our galaxy, waking up the black hole that lives at its centre and turning our galaxy into an 'active galactic nucleus' or quasar."
With sufficient matter falling into the hole, these can become extremely luminous, and are seen as a quasar or active galactic nucleus (AGN).
If a substantial fraction of this gas fell onto the black hole over the course of a few years, Sgr A* would morph into something akin to an active galactic nucleus (AGN), similar to those we observe in galaxies in the far reaches of the universe.
(2003) Cosmological evolution of the hard X-ray active galactic nucleus luminosity function and the origin of the hard X-ray background.
Urry, "Active galactic nucleus black hole masses and bolometric luminosities," The Astrophysical Journal, vol.
"It's a step along the road to an ambitious goal of imaging a black hole in a galactic nucleus."
light from the quasar, a galactic nucleus fed by a black hole, began travelling toward us 12.9 billion years ago, when the universe was only 770 million years old.
Each such area is known as an active galactic nucleus (called AGN).
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