Primary caustics and critical points behind a Kerr black hole
| dc.creator | Sereno, M. | |
| dc.creator | De Luca, F. | |
| dc.date | 2007-10-31 | |
| dc.date | 2008-06-13 | |
| dc.date.accessioned | 2026-07-07T12:13:51Z | |
| dc.date.available | 2026-07-07T12:13:51Z | |
| dc.description | The primary optical caustic surface behind a Kerr black hole is a four-cusped tube displaced from the line of sight. We derive the caustic surface in the nearly asymptotic region far from the black hole through a Taylor expansion of the lightlike geodesics up to and including fourth-order terms in m/b and a/b, where $m$ is the black hole mass, a the spin and b the impact parameter. The corresponding critical locus in the observer's sky is elliptical and a point-like source inside the caustics will be imaged as an Einstein cross. With regard to lensing near critical points, a Kerr lens is analogous to a circular lens perturbed by a dipole and a quadrupole potential. The caustic structure of the supermassive black hole in the Galactic center could be probed by lensing of low mass X-ray binaries in the Galactic inner regions or by hot spots in the accretion disk. | |
| dc.description | 7 pages, 5 figures; v2: extended discussion, 2 figures added, results unchanged; in press on PRD | |
| dc.identifier | https://arxiv.org/abs/0710.5923 | |
| dc.identifier | http://arxiv.org/abs/0710.5923 | |
| dc.identifier | Phys.Rev.D78:023008,2008 | |
| dc.identifier | doi:10.1103/PhysRevD.78.023008 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/210989 | |
| dc.subject | Astrophysics | |
| dc.subject | General Relativity and Quantum Cosmology | |
| dc.title | Primary caustics and critical points behind a Kerr black hole | |
| dc.type | text |