Light trajectories and shadows of slowly rotating wormholes in void environments
Abstract
We explore slowly rotating traversable wormholes placed inside realistic cosmic voids, focusing on three types: compensated voids, top-hat voids, and exponential voids. Using the standard Teo-type rotating wormhole metric, we build the wormhole geometry from the void density, looking at features like the throat shape, how sharply it flares out, and where the usual energy conditions are violated. We then follow how light moves in these spacetimes. Photon paths, circular orbits, and the small twisting caused by rotation (Lense-Thirring (LT) effect) all change depending on the void. Steep, concentrated voids such as compensated ones tend to pull photons closer and create asymmetry, while smoother voids like top-hat and exponential types allow photons to move more evenly, forming nearly circular paths. Finally, we look at the shadows these wormholes would cast. Wormholes in compensated voids produce smaller, slightly distorted shadows, while smoother voids give larger, rounder, and more symmetric silhouettes. Altogether, this shows how the void’s structure, combined with slow rotation, shapes both photon motion and the appearance of the wormhole shadow from a distance.