This
Astrobin Debut Object is a galaxy group of 7 galaxies, called Hickson 25, located in the constellation of Cetus at a declination of -1 degrees. This is not a true cluster. 4 of the galaxies (a, b, d and f) are at the same distance of 300 million light years away, while 2 others (c and e) are 0.5 billion light years away. As often happens in a Hickson group, the dimmest galaxy and therefore the last one in the alphabet (g) is the furthest away at 0.6 billion light years.
The largest, brightest and most interesting galaxy, Hickson 25a, is a magnitude 14 blue spiral. It spans 1.5 arc-minutes, which corresponds to a Milky Way size diameter of 120,000 light years. I love the arm structure of the top half - it looks like a single strong arm extends up and to the right.
**************************************************
The Hickson catalog is a collection of 100 galaxy groups, established by Paul Hickson in 1982. Hickson compact galaxy groups are tightly spaced and somewhat isolated 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