NGC 5128 – Caldwell 77 – Centaurus A

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Click on the image to see a larger version                   New, deeper version (see details below)

 

NGC 5128 is a peculiar elliptical galaxy with an enormous dust lane crossing at its central zone. This galaxy is the result of a merger between two galaxies, the main elliptical one is “swallowing” a smaller spiral, according to a research conducted with the Spitzer telescope. This galaxy has, mainly highly evolved redder stars, but its dust lane has regions with active star formation (bluer areas on its lower right corner). A supermassive black hole is believed to lay in the galaxy’s center and to be responsible for its strong X-ray and radio emissions.

The second version is a much deeper one. A friend of mine, Christian Sasse, pointed out that this galaxy had a much more complex structure than the usual images reveal. He challenged me enough to try to glimpse more of this structure, taking more (and longer) subframes.  This version has 39x300s Luminance exposures added to the first one. With this extra light, a much more detailed dust structure can be observed, extending much farther out than it can be seen in the first image, even showing small dots, on the left of the central lane, that could not be glimpsed before. Remarkable is the presence of the very faint external arc (see below) that needed this extra exposure to pop up. This arc of young stars seems to be the remains of one of NGC 5128’s galactic mergers. It may also look as part of a “shell”, just like NGC 1316 does, but much less conspicuous.

The image has been taken with a NABG camera, and hence the brightest stars “bleed”. The did not do so in the first version, because the exposures were much shorter.

 

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Additional Information

Object

Name(s): NGC 5128. Caldwell 77. Centaurus A

Type: Elliptical galaxy

RA:  13h 25m 28s

Dec: -43º 00’ 50.7”

Constellation: Centaurus

Size (arcmin): 26×20

Magnitude: +6.8

Distance: 11 Mly

Image

Date: 2013-07-27 (the extra 39x5min L subframes, on 2017-03-02)

Location: iTelescope.net, SSO near Coonabarabran, NSW Australia

Size (arcmin): 42×27

Telescope: Planewave CDK 20” f/4.5

Camera: FLI PL6303E (3072×2048 px)

Guiding: yes

Total exposure: 213 min (L: 39x5min + 6xRGBx1min)

Processing: CCDStack, Photoshop CC 2017 and PixInsight

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