Credit: NASA, ESA, and P. Marshall and T. Treu(University of California, Santa Barbara)
This photo illustration shows a tiny galaxy 6 billion light-years away that is smaller than any galaxy ever seen at that distance.
Astronomers discovered this distant galaxy through a phenomenon called gravitational lensing. This phenomenon occurs when a massive galaxy in the foreground bends the light rays from a distant galaxy behind it in much the same way as a magnifying glass does. When both galaxies are exactly lined up, the light forms a bull's-eye pattern, called an "Einstein ring," around the foreground galaxy.
This ring can be seen in the illustration. Einstein rings are named for physicist Albert Einstein, who predicted the phenomenon. By focusing the light rays, this gravitational lensing effect increases the observed brightness and size of the background galaxy by more than 10 times.
The illustration is based on images taken in infrared light from the W. M. Keck Telescope and visible-light images from NASA's Hubble Space Telescope. The Hubble and Keck data reveal information about the early years of the infant galaxy, namely that it is seen just after it formed most of its stars.
The Hubble images were taken on Nov. 5, 2006 with the Advanced Camera for Surveys and the Near Infrared Camera and Multi-Object Spectrometer. The Keck images were taken on Dec. 11, 2006.
This is a color composite image of the gravitational lens system, made from Hubble (blue and green filters) and Keck (red filter) data. The blue ring is the tiny background galaxy that is being stretched by the gravitational pull of the foreground "lens" galaxy at the center of the image.
