This
Astrobin Debut Object is a galaxy group of 4 galaxies, called Hickson 19, located in the constellation of Cetus at a declination of -12 degrees.
This is not a true cluster. Galaxies a, b and c are all at approximately the same distance away of 200 million light years. Galaxies b and c show some interesting structure. I see a bit of disturbance in these galaxies, so they may be close enough to each other to be interacting.
Galaxy d is much further away at almost 1 billion light years and is the largest galaxy here in actual size at 130,000 light years in diameter.
The brightest galaxy of the group, Hickson 19a, is also known as LEDA 10262. It is a magnitude 13.0 galaxy which spans 45 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.
Comments