This
Astrobin Debut Object is a galaxy group of 5 small galaxies, called Hickson 24, located almost 0.5 billion light years away in the constellation of Eridanus at a declination of -11 degrees. This is a true cluster -the 5 galaxies are all at approximately the same distance. I see some possible disturbance here in the slightly asymmetric shapes of a few of the galactic halos, especially the left galaxy (24b), so perhaps they are close enough to each other to be interacting.
Compared to the typical Hickson group, Hickson 24 is a bit further away (at 430 mly), slightly smaller in overall size (at 2.4 arc-minutes overall diameter), and slightly dimmer in brightness (at 12.7 group magnitude). The brightest galaxy of the group, Hickson 24a, is also known as LEDA 12477. It is a magnitude 13.6 galaxy which spans 25 arc-seconds. This corresponds to a small actual diameter of 50,000 light years.
The Hickson catalog is a collection of 100 galaxy groups, established by Paul Hickson in 1982. Hickson compact galaxy groups are strictly defined by 3 criteria: number of galaxies, total magnitude, and isolation from other galaxies. A typical Hickson group has 4 galaxies, but some have up to 8. You can see more about Hickson galaxy groups in my
Astrobin Hickson Collection.
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