- Ville Puoskari
This interesting pair of galaxies lies approx. 20 million light-years from Earth. The galaxy on the left (NGC4631) is nicknamed as the whale galaxy. It contains a central starburst region that has very intense star formation. So many supernovae have exploded in the center of NGC 4631 that some of the gas from these explosions has pushed out of the plane of this galaxy. This phenomena has also created a giant corona of hot gas around the entire galaxy, it is visible in X-ray observations.
On the right side you can see another galaxy (NGC4656), it is crooked and dispersed in many ways. This is due to gravitational interaction with the whale galaxy. According to some sources the hook of the galaxy is actually a satellite galaxy of NGC4656.