Massless braneworld black hole lenses (presentacion oral)

ERNESTO F. EIROA; CARLOS M SENDRA (EXPOSITOR)

Villa General Belgrano, Córdoba

Conferencia; Grav 13; 2013

FAMAF, Universidad de Córdoba, Argentina

Black holes distort the spacetime structure in their surroundings. As a consequence, the light rays passing close to them are bent, so black holes can be considered as gravitational lenses. In braneworld cosmological models, the ordinary matter is on a three dimensional space called the brane, which is embedded in a larger space denominated the bulk, where only gravity can propagate. All the properties of black holes, including gravitational lensing effects, will be different due to the presence of extra dimensions. In this work, we study massless black holes as gravitational lenses, in the Randall-Sundrum braneworld scenario. We perform the weak deflection limit (corresponding to a small deflection angle, which can be approximated to first order in 1/r) to obtain the positions and the magnifications of the primary and secondary images of a point source. Photons passing close to the black hole, experiment one or more loops around it before they emerge to the observer, and will give place to two infinite set of relativistic images of the source. In this case, the deflection angle is obtained by an asymptotical logarithmic approximation called the strong deflection limit, which allows an analytical study of the positions and the magnifications of these images.