Shadows and optical appearance of black bounces illuminated by a thin accretion disk

Abstract

We study the light rings and shadows of an uniparametric family of\nspherically symmetric geometries interpolating between the Schwarzschild\nsolution, a regular black hole, and a traversable wormhole, and dubbed as black\nbounces, all of them sharing the same critical impact parameter. We consider\nthe ray-tracing method in order to study the impact parameter regions\ncorresponding to the direct, lensed, and photon ring emission, finding a\nbroadening of all these regions for black bounce solutions as compared to the\nSchwarzschild one. Using this, we determine the optical appearance of black\nbounces when illuminated by three standard toy models of optically and\ngeometrically thin accretion disks viewed in face-on orientation.\n