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In 1963 Yu. G. Klimov, S. Liebes, and Sjur Refsdal recognized independently that quasars are an ideal light source for the gravitational lens effect. [23] It was not until 1979 that the first gravitational lens would be discovered. It became known as the "Twin QSO" since it initially looked like two identical quasistellar objects.
In weak gravitational lensing, the Jacobian is mapped out by observing the effect of the shear on the ellipticities of background galaxies. This effect is purely statistical; the shape of any galaxy will be dominated by its random, unlensed shape, but lensing will produce a spatially coherent distortion of these shapes.
In particular, gravitational lensing provides one way to measure the distribution of dark matter, which does not give off light and can be observed only by its gravitational effects. One particularly interesting application are large-scale observations, where the lensing masses are spread out over a significant fraction of the observable ...
For a source right behind the lens, θ S = 0, the lens equation for a point mass gives a characteristic value for θ 1 that is called the Einstein angle, denoted θ E. When θ E is expressed in radians, and the lensing source is sufficiently far away, the Einstein Radius , denoted R E , is given by
Abell 370 is a galaxy cluster located nearly 5 billion light-years away from the Earth (at redshift z = 0.375), in the constellation Cetus. [3] Its core is made up of several hundred galaxies. It was catalogued by George Abell , and is the most distant of the clusters he catalogued.
The key difference between an embedded lens and a traditional lens is that the mass of a standard lens contributes to the mean of the cosmological density, whereas that of an embedded lens does not. Consequently, the gravitational potential of an embedded lens has a finite range, i.e., there is no lensing effect outside of the void.
Petters is known for his work in the mathematical theory of gravitational lensing.. Over the ten-year period from 1991 to 2001, Petters systematically developed a mathematical theory of weak-deflection gravitational lensing, beginning with his 1991 MIT Ph.D. thesis on "Singularities in Gravitational Microlensing". [12]
Gravitational lensing is an effect of gravitation, most commonly associated with General relativity. Subcategories. This category has the following 2 subcategories ...