From The Southen Sky Gems Observatory at Tivoli AstroFarm
What's the closest active galaxy to planet Earth? And what's the fifth brightest in Earth's sky (though visible from low northern latitudes and the southern hemisphere)? That would be Centaurus A, only 11 million light-years distant. Spanning over 60,000 light-years, the peculiar elliptical galaxy is also known as NGC 5128. Forged in a collision of two otherwise normal galaxies, Centaurus A's fantastic jumble of young blue star clusters, pinkish star forming regions, and imposing dark dust lanes are seen here in remarkable detail. The colorful galaxy portrait was recorded under clear Namibian skies at the Southern Sky Gems Observatory at the Kalahari Desert. Near the galaxy's center, left over cosmic debris is steadily being consumed by a central black hole with a billion times the mass of the Sun. As in other active galaxies, that process likely generates the radio, X-ray, and gamma-ray energy radiated by Centaurus A.
Spanning 25′.7 × 20′.0 on Earth's sky, and at an apparent magnitude of 6.84, Centaurus A was discovered in 1826 by Scottish astronomer James Dunlop from his home in Parramatta, in New South Wales, Australia. The galaxy's active galactic nucleus has been extensively studied by professional astronomers, and contains a supermassive black hole with a mass equivalent to 55 million solar masses,which ejects a relativistic jet that is responsible for emissions in the X-ray and radio wavelengths. By taking radio observations of the jet separated by a decade, astronomers have determined that the inner parts of the jet are moving at about one half of the speed of light. X-rays are produced farther out as the jet collides with surrounding gases resulting in the creation of highly energetic particles. The radio jets of Centaurus A are over a million light years long.
(Ref.
http://apod.nasa.gov/apod/ap120404.html;
https://en.wikipedia.org/wiki/Centaurus_A)
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