Coloquio Departamental/Colloquium

Pushing the Analogy: Lensing by a Schwarzschild Black Hole / Dr. Omar López Cruz (INAOE)

America/Mexico_City
Auditorio José Adem

Auditorio José Adem

Description

We present a new approach for evaluating the optical properties of gravitational lensing by a Schwarzschild black hole (S-BH). Optical analogies can be used to exploit the properties of gravitational lensing. It is possible to generate axially symmetric lens models to reproduce the effects of gravitational lensing by a given mass distribution such as a point mass, a singular isothermal sphere, or a uniform disk (as introduced by Refsdal & Surdej in 1994). Nevertheless, there is no published optical analogy to reproduce the effects of S-BH. We have used new the formalism introduced by Gómez-Correa et al (2022), which is a ray tracing generalization in a symmetric gradient-index media by Fermat`s ray invariants, to show that is possible to generate a lens made of a gradient-index (GRIN) media that reproduces the trajectories of photons as they approach the radius of closest approach, r_photosphere = 3GM/c where G is the gravitational constant, M is the black hole mass and c is the velocity of light. Our approach reproduces orbital light and  the  plunge of light inside the S-BH.  This insight would help us to measure the mass of ultramassive black holes in cD galaxies using high-resolution sub-mm observations.

Organized by

Dr. Ivan Heredia de la Cruz