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.

Centaurus A

[sen′tȯr·əs ′ā]
(astronomy)
A strong, discrete radio source in the constellation Centaurus, associated with the peculiar galaxy NGC 5128.
References in periodicals archive ?
Centaurus A, also known as NGC 5128, is visible only from the Southern Hemisphere.
7, open cluster C 97, ASSA 46 NGC 3918, Blue Planetary, planetary nebula ESO 170-13, ASSA 47 M 84, NGC 4374, Markarian galaxy Chain, LEDA 40455 M 86, NGC 4406, Markarian galaxy Chain, LEDA 40653 M 87, NGC 4486, Virgo galaxy Galaxy, Smoking Gun Jaws Asterism, Sombrero's asterism Arrow M 104, NGC 4594, Sombrero galaxy Galaxy, ASSA 50 NGC 4945, Tweezers, Ben 57, galaxy C 83, ASSA 54 NGC 5128, Centaurus A, Ben galaxy 60, C 77, ASSA 55 NGC 5139, Omega Centauri, globular cluster C 80, ASSA 56 NGC 5286, Dunlop 388, GCl globular cluster 26, Ben 64, C 84 NGC 5281, Lacaille I.
NGC 5128 (Centaurus A) is a bright galaxy that can be seen in binoculars as a 7th magnitude fuzzy star, looking a bit like a globular cluster.