Galaxy group in Coma (NGC 4725, NGC 4712, NGC 4747, PGC 86434)

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About this Image

This group of galaxies is situated in the constellation Coma Berenices dominated by the supergiant NGC4725 as most prominent galaxy at a distance of approx. 50 million light years. Unlike most of the other galaxies NGC 4725 exhibits just one spiral arm tightly wound around the core. Blue star forming areas are dominating the structure of the single spiral arm, closer to the center bulge older yellow star populations are dominating.

At the top left corner of this image there is the mag 13.7 background spiral NGC 4712 at a distance of approx. 200 million light years.

Tidal interaction with the massive spiral NGC 4725 is the generally accepted cause for the severe distortion of the smaller galaxy NGC 4747 (also known as ARP 159) at similar distance to the bottom right corner of this image. Several faint tidal loops indicate the turbulent history of that galaxy.

To the lower left side of this image the blueish mag 17.5 galaxy PGC 86434 is estimated to reside in a distance of approx 50 million light years.

Most of the visible objects in this image are faint background galaxies (mag 18-22) showing up in a filamentary structure, typically in yellowish color as obscured by intergalactic dust.

South is up.

Find a infrared composite image of NGC 4725 by the Spitzer telescope here.


Technical Details


16" cassegrain in corrected secondary focus at f/10

Mount ASA DDM-85XL
Camera SBIG STX16803 at -30C, STX filter wheel
Filters Baader 65x65mm LRGB
Date April 2011
Location Wildon/Austria
Sky Conditions mag 5-5.5 sky, raw FWHM 1.5-2.5", temperature 10-17 C
Exposure L:R:G:B = 480:120:120:160 minutes (20-minute sub-exposures)
Programs used Autoslew
Maxim DL 5
Photoshop CS5