Contact: Lynn Chandler
lynn.chandler-1@nasa.gov
301-286-2806
NASA/Goddard Space Flight Center

Rare Cases of Galaxy-Quasar Combinations

Caption: To find these rare cases of galaxy-quasar combinations acting as lenses, a team of astronomers led by Frederic Courbin at the Ecole Polytechnique Federale de Lausanne (EPFL, Switzerland) selected 23,000 quasar spectra in the Sloan Digital Sky Survey (SDSS). They looked for the spectral imprint of galaxies at much greater distances that happened to align with foreground galaxies. Once candidates were identified, Hubble's sharp view was used to look for gravitational arcs and rings (which are indicated by the arrows in these three Hubble photos) that would be produced by gravitational lensing.

Credit: Image Credit: NASA, ESA, and F. Courbin (EPFL, Switzerland)

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