This is an “Einstein Ring” or gravitational lensing. The blue galaxy is behind the yellow galaxy. We can see the blue galaxy because light from the far galaxy gets wrapped around by the closer galaxy. Photo courtesy of Hubble.
This Hubble Space Telescope view reveals thousands of galaxies stretching back into time across billions of light-years of space. The image covers a portion of a large galaxy census called the Great Observatories Origins Deep Survey (GOODS).