Gravitational lensing by two photon spheres in a black-bounce spacetime\n in strong deflection limits

Abstract

We investigate gravitational lensing by a primary photon sphere which is a\nsphere filled with unstable circular light orbits, and by a secondary photon\nsphere on a wormhole throat in a black-bounce spacetime which is suggested in\n[F. S. N. Lobo, M. E. Rodrigues, M. V. d. S. Silva, A. Simpson, and M. Visser,\nPhys. Rev. D 103, 084052 (2021)] in strong deflection limits. There is an\nantiphoton sphere between the primary photon sphere and the secondary photon\nsphere. If a light source and an observer are on the same side of the wormhole\nthroat, in addition to an infinite number of images slightly outside of both\nthe primary and secondary photon spheres, an infinite number of images formed\nby light rays reflected by the potential barrier near the antiphoton sphere,\nslightly inside the primary photon sphere, might be observed.\n