2006/09/30 by M. Sereno, F. De Luca
Physics and Astronomy · #Angular momentum #Astrophysical Phenomena and Observations #Astrophysics #Black hole (networking) #Caustic (mathematics) #Charged black hole #Classical mechanics #Experimental and Theoretical Physics Studies #Extremal black hole #Galaxy #General relativity #Geodesic #Geometry #Gravitation #Gravitational lens #Mathematical physics #Photon sphere #Physics #Pulsars and Gravitational Waves Research #Rotating black hole #Schwarzschild metric #Schwarzschild radius #Spin-flip #Strong gravitational lensing #Supermassive black hole #astro-ph #gr-qc
paper · pdf · doi:10.1103/physrevd.74.123009
published as Phys.Rev. D74 (2006) 123009 · 12 pages; minor changes to match the version in press on Phys. Rev. D
arxiv created 2006/12/18 · openalex publication_date 2006/12/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present an analytical treatment of gravitational lensing by a Kerr black hole in the weak deflection limit. Lightlike geodesics are expanded as a Taylor series up to and including third-order terms in m/b and a/b, where m is the black hole mass, a the angular momentum, and b the impact parameter of the light ray. Positions and magnifications of individual images are computed with a perturbative analysis. At this order, the degeneracy with the translated Schwarzschild lens is broken. The critical curve is still a circle displaced from the black hole position in the equatorial direction and the corresponding caustic is pointlike. The degeneracy between the black hole spin and its inclination relative to the observer is broken through the angular coordinates of the perturbed images.