Separability of rotational effects on a gravitational lens

Jan, 2003
12 pages
Published in:
  • Phys.Rev.D 67 (2003) 043006
e-Print:

Citations per year

200420092014201920241023
Abstract: (arXiv)
We derive the deflection angle up to O(m2a)O(m^2a) due to a Kerr gravitational lens with mass mm and specific angular momentum aa. It is known that at the linear order in mm and aa 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. Furthermore, it is distinguishable also for each image of an extended source and/or a point source in orbital motion. In practice, the correction at O(m2a)O(m^2a) becomes O(1010)O(10^{-10}) for the supermassive black hole in our galactic center. Hence, these nonlinear gravitational lensing effects are too small to detect by near-future observations.
  • 98.62.Sb
  • 04.70.Bw
  • 95.30.Sf