This image captures a pair of spiral galaxies in the constellation of Coma Berenices at a declination of +25 degrees. The galaxies are at much different distances and are not interacting. The smaller galaxy in the image is the largest galaxy in actual size.
The galaxy at left is NGC 4725, a barred spiral galaxy located 40 million light years away. It is a magnitude 12.5 galaxy which spans 10 arc-minutes in our apparent view. This corresponds to a Milky Way like diameter of 120,000 light years. This galaxy, which is tilted towards us at about 45 degrees, has many interesting features:
- It is a magnitude 12.5 Seyfert galaxy with an active galactic nucleus, which means the luminosity of the core is brighter than normal.
- The central bar is actually a warped, curving structure. Scientists have identified that it actually consists of two bars, of two different sizes, rotating independently from each other.
- Surrounding the core region is a bright blue ring of star clusters, which contrasts nicely with the yellowish core.
- This galaxy appears to have only one very long arm, making 2-1/2 revolutions around the core.
- The above unusual structures are believed to be the result of gravitational interactions with nearby NGC 4747, which is not seen in this image.
The smaller galaxy at right is NGC 4712, inclined about 20 degrees from edge-on. It is larger in actual size at about 150,000 light years in diameter but is five times further away at 200 million light years so it appears much smaller to us. Even at this distance, its core, spiral structure and star clusters are clearly seen.
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