This object is a galaxy group of 4 galaxies, called Hickson 53, located in the constellation of Leo at a declination of +21 degrees.
The 3 largest galaxies of the group (a, b and c) are all from 280 to 300 million light years away. They appear to be just far enough apart not to be interacting with each other. The smallest galaxy, 53d, is also the furthest, at 420 million light years.
The largest and brightest galaxy, Hickson 53a, is also known as NGC 3697. It is a magnitude 12 grand design spiral galaxy. We are viewing the galaxy disk at about 15 degrees from edge-on. The galaxy spans 2 arc-minutes in our apparent view which corresponds to a large diameter of 170,000 light years. The galaxy arms are hard to trace at the inclined disk angle, but they appear to have several straight VV rows within them along with several blue star clouds.
54b is an interesting double ring spiral with a yellow inner lens. The mid-region ring is bright but the outer ring is very faint and barely visible.
54c is the most fascinating galaxy of the bunch. I do not understand the structure. 2 strong arms emanate from what look likes a long bar, but other activity is also seen in the inner region including 2 bright blue star clouds.
54d is the most distant and least interesting galaxy, a small edge-on spiral without much detail.
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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