Throat effects on shadows of Kerr-like wormholes

Abstract

We revisit to investigate shadows cast by Kerr-like wormholes. The boundary of the shadow is determined by unstable circular photon orbits. We find that, in certain parameter regions, the orbit is located at the throat of the Kerr-like wormhole, which was not considered in the literature. In these cases, the existence of the throat alters the shape of the shadow significantly, and makes it possible for us to differentiate it from that of a Kerr black hole.