Separability of rotational effects on a gravitational lens

  title={Separability of rotational effects on a gravitational lens},
  author={Hideki Asada and Masumi Kasai and Tatsuya Yamamoto},
  journal={Physical Review D},
We derive the deflection angle up to $O(m^2a)$ due to a Kerr gravitational lens with mass $m$ and specific angular momentum $a$. It is known that at the linear order in $m$ and $a$ the Kerr lens is observationally equivalent to the Schwarzschild one because of the invariance under the global translation of the center of the lens mass. We show, however, nonlinear couplings break the degeneracy so that the rotational effect becomes in principle separable for multiple images of a single source… 
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The classical theory of fields
The principle of relativity Relativistic mechanics Electromagnetic fields Electromagnetic waves The propagation of light The field of moving charges Radiation of electromagnetic waves Particle in a