Chagoya Saldaña, Javier Fernando; Ortiz, C.; Rodríguez, Benito; Roque, Armando A.
Resumen:
The deflection of light in the strong field limit is an important test for
alternative theories of gravity. However, solutions for the metric that allow for analytic
computations are not always available. We implement a hybrid analytic-numerical
approximation to determine the deflection angle in static, spherically symmetric
spacetimes. We apply this to a set of numerical black hole solutions within the class
of theories known as Degenerate Higher Order Scalar-tensor Theories. Comparing
our results to a more time consuming full numerical integration, we find that we can
accurately describe the deflection angle for light rays passing at arbitrary distances
from the photon sphere with a combination of two analytic-numerical approximations.
Furthermore, we find a range of parameters where our DHOST black holes predict
strong lensing effects whose size is comparable with the uncertainty in the properties of
the supermassive black hole in M87 reported by the Event Horizon Telescope, showing
that strong lensing is a viable alternative to put constraints on these models.