Four galaxies colliding have been photographed by NASA’s Chandra X-Ray Observatory and by the Hubble telescope. These are composite images from:
- X-rays (Blue, Violet)
- Optical (Cyan, Yellow)
Details about the galaxies, and many more images can be found at the Chandra site at Harvard. Animations there too.
An excellent and fairly brief explanation of how the pictures are taken, and why they look as they do is found on this page: Chandra Images & False Color.
Ponder and enjoy,