Examples of gravitational lensing -- beautiful clusters of galaxies showing arcs
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Galaxy cluster Abell 1689 HST/ACS image |
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Galaxy cluster Abell 2218 HST/ACS image |
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Arc in Abell 370 |
Principle of gravitational lensing -- from the Einstein ring to galaxy clusters with arcs
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Spherical mass and source perfectly aligned --> Einstein ring
Ellipsoidal mass distribution and perfect alignment --> quadruple images
Irregular mass distribution (cluster of galaxies with dark mass) --> numerous arcs / lenslets |