Slacs gravitational lens candidates

This collection of images shows 28 gravitational lens candidates. Astronomers studied these photos, which were taken by the Hubble Space Telescope's Advanced Camera for Surveys , and identified which of the candidates were gravitational lenses. These candidates were selected from the Sloan Digital Sky Survey . Gravitational lensing occurs when the gravitational field from a massive object warps space and deflects light from a distant object behind it. The reddish-white objects in the center of each image are massive galaxies. The blue arc-like patterns around many of the galaxies are the smeared light from distant galaxies that are behind the massive galaxies.