Weak Lensing Observables
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.
Read more about this topic: Gravitational Lensing Formalism
Famous quotes containing the word weak:
“The weak have one weapon: the errors of those who think they are strong.”
—Georges Bidault (1899–1983)