Cluster Lensing
The foreground lens is a galaxy cluster. In this case, the lens is usually powerful enough to produce noticeable both strong lensing (multiple images, arcs or rings) and weak lensing effects (ellipticity distortions).
Read more about this topic: Strong Gravitational Lensing
Famous quotes containing the word cluster:
“Next week Reagan will probably announce that American scientists have discovered that the entire U.S. agricultural surplus can be compacted into a giant tomato one thousand miles across, which will be suspended above the Kremlin from a cluster of U.S. satellites flying in geosynchronous orbit. At the first sign of trouble the satellites will drop the tomato on the Kremlin, drowning the fractious Muscovites in ketchup.”
—Alexander Cockburn (b. 1941)