Centaurus A
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Discovered by James Dunlop in 1826.

This galaxy is situated in the M83 group of galaxies. It is one of the most interesting 
and peculiar galaxies in the sky, and is a strong source of radio radiation (therefore 
the designation Centaurus A); it is actually the nearest radio galaxy. It is of 
intermediate type between elliptical and disk (spiral) galaxies: The main body has all 
characteristics of a large elliptical, but a pronounced dust belt is superimposed well 
over the center, forming a disk plane around this galaxy.

This galaxy seems to have "eaten" at least one larger spiral in the last few billion 
years. However, the present author is not sure if this alone explains the unique 
appearance of this galaxy: It may well be that this is one of the rare "links" between 
"normal" ellipticals and "normal" disks.

In the radio part of the spectrum, Centaurus A exhibits two vast regions of radio 
emission, starting in prolongation of the polar axis of the disk of NGC 5128 and 
extending many hundreds of light years to each side.

Our image was obtained by David Malin with the Anglo-Australian Telescope. This image 
is copyrighted and may be used for private purpose only. For any other kind of use, 
including internet mirroring and storing on CD-ROM, please contact the Photo Permissions 
Department (photo at aaoepp.aao.gov.au) of the Anglo Australian Observatory.

The bright blue-green star in the middle of the left part of the dust belt in this image 
is supernova 1986G (the only SN discovered in Centaurus A so far) which was discovered 
on May 3, 1986, by Reverend Robert Evans, and reached mag 12.5 (see IAUC 4208). The 
blue-green color occurs because David Malin could take the red plate used in this 
composite image only one year after the supernova occurred, and it had faded away at 
that time.

NGC 5128 was discovered by James Dunlop on August 4, 1826, and cataloged by him as 
Dun 482. John Herschel was the next to see it on June 1, 1834 from South Africa, and 
cataloged it as h 3501, which became GC 3525 in his General Catalogue of 1864, and 
NGC 5128 in J.L.E. Dreyer's NGC.

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Why is peculiar galaxy Centaurus A so dusty? Dramatic dust lanes that run across the 
galaxy's center mark Cen A. These dust lanes are so thick they almost completely obscure 
the galaxy's center in visible light. This is particularly unusual as Cen A's red stars 
and round shape are characteristic of a giant elliptical galaxy, a galaxy type usually 
low in dark dust. Cen A, also known as NGC 5128, is also unusual compared to an average 
elliptical galaxy because it contains a higher proportion of young blue stars and is a 
very strong source of radio emission. Evidence indicates that Cen A is likely the result 
of the collision of two normal galaxies. During the collision, many young stars were 
formed, but details of the creation of Cen A's unusual dust belts are still being 
researched. Cen A lies only 13 million light years away, making it the closest active 
galaxy. Cen A spans 60,000 light years and can be seen with binoculars toward the 
constellation of Centaurus.

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The Hubble telescope offers a stunning unprecedented close-up view of a turbulent 
firestorm of star birth along a nearly edge-on dust disk girdling Centaurus A, the 
nearest active galaxy to Earth. The picture at upper left shows the entire galaxy. 
The blue outline represents Hubble's field of view. The larger, central picture is 
Hubble's close-up view of the galaxy. Brilliant clusters of young blue stars lie 
along the edge of the dark dust lane. Outside the rift the sky is filled with the 
soft hazy glow of the galaxy's much older resident population of red giant and red 
dwarf stars.