Lyon Triplets

This interacting Galaxy triplet (sometimes referred to as the Lyon Triplet) is located in the constellation of Grus.

At the top of the image is PGC 68443 also referred to as NGC 7232B located at a distance of 91 million light years from here. PGC 68443 is a spiral galaxy with numerous star forming areas.

Bottom center is NGC 7233 at a distance of 78 million light years. It is variously classified as barred spiral and lenticular. By appearance despite the rather diffuse arms I would classify it as barred spiral.

At the bottom right is NGC 7232 at a distance 82 million light years. It is classified as lenticular and exhibits multiple dust lanes.

Of interest the group is thought to contain a dark galaxy. This is a rare object that contains the raw ingredients for making stars but which hasn't been able to form any. The dark galaxy is thought to have enough gas to make more than 400 million Suns.

It is likely, that a massive quantity of gas was expelled from NGC 7233 sometime in the past during a close encounter with one of the other two galaxies.

The image shows evidence of this, as streams of what appears to be gaseous debris can be seen between the three galaxies.

This is supported by the MeerKat 64 detection of significant amounts of tidal debris within the group.

The galaxies in the group are small with NGC 7233 at an apparent FOV of 1.7x1.3’ NGC 7232 at 2.3x1’ and and PGC 68443 at 1.7x1.5’

Imaged in LRGB on my Planewave CDK 1000 at Observatorio El Sauce, Chile.

Image acquisition and processing: Mike Selby