Centaurus A

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Centaurus A

An intense radio and X-ray source in the southern constellation Centaurus and a source also of infrared radiation and gamma rays. It is identified with the galaxy NGC 5128 lying at a distance of only 5 megaparsecs from the Solar System, making it the nearest active galaxy. It is an elliptical galaxy, 100 kpc in diameter, cut across by broad belts of gas and dust. A complex elongated radio structure emerges from the center of the gas and dust belts, approximately along their axis of rotation and extending about 400 kpc in each direction. The radio structure consists broadly of two large lobes more or less symmetrically disposed about a central nucleus, from which a jet extends toward one of the lobes. The jet is broken up into a number of knots. This huge radio galaxy, stretching over 9° of the sky, has a flux density at 86 megahertz of 8700 jansky, believed to be synchrotron emission.

Centaurus A is also one of the brightest hard X-ray sources, its spectrum being measured to about 200 kiloelectronvolts. It is also variable on timescales down to a few days, suggesting that most of the X-ray emission arises in the nucleus. An Einstein Observatory image showed not only the bright nucleus but in addition a line of sources, i.e. an X-ray jet, significantly along the axis of the radio lobes. The X-ray emission follows closely the radio jet but extends beyond it into the radio lobe.

Collins Dictionary of Astronomy © Market House Books Ltd, 2006

Centaurus A

[sen′tȯr·əs ′ā]
(astronomy)
A strong, discrete radio source in the constellation Centaurus, associated with the peculiar galaxy NGC 5128.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
IN THE FEBRUARY 2ND Science, Oliver Muller (University of Basel, Switzerland) and colleagues report that satellite galaxies are moving around the huge elliptical Centaurus A (NGC 5128) in an orderly fashion.
One of the most interesting nearby galaxies is NGC 5128 (Centaurus A) (see [20], for a review of the properties of Cen A), the closest, most easily observable giant elliptical galaxy [21].
The first of two objects - both of which were discovered using NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton Observatory - is located near the NGC 4636 galaxy at a distance of 47 million light-years from Earth, while the other one is located in the vicinity of the NGC 5128 galaxy, which is roughly 14 million light-years away.
Centaurus A (NGC 5128) is the nearest giant, elliptical galaxy, at a distance of about 11 million light-years.
Centaurus A, also known as NGC 5128, is visible only from the Southern Hemisphere.
This exceedingly deep image reveals faint shells of stars that extend far beyond the familiar bright core and dust lane in active galaxy NGC 5128.
Its members include the iconic M83 and Centaurus A (NGC 5128), leading it sometimes to be called the M83/Cen A Group.
The nearest active galactic nucleus is the one 12 million light-years away in the peculiar giant galaxy NGC 5128, also known as Centaurus A from the early days of radio astronomy.
NGC 5128, known as Centaurus A, is a bright peculiar galaxy, thought to be a giant elliptical galaxy devouring a dusty spiral.
Instead, their arrival directions appear to match the distribution on the sky of active galaxies within a few hundred million light-years of us--and in particular NGC 5128 (Centaurus A) only 12 million light-years away.
He described the dozen or so 6th- to 11th-magnitude stars within this 10'-wide open cluster as a "casket of variously coloured precious stones." In Centaurus my eyes feasted on the magnificent naked-eye globular cluster NGC 5139, Omega Centauri, and the giant peculiar galaxy NGC 5128, also known as Centaurus A, which flaunted its famous dust lane.
Both M83 and NGC 5128 (mentioned here last month) belong to the same small group of galaxies, some 10 million light-years from us.