We discuss photon rings around as well as shadows of Kerr black holes immersed in a swirling spacetime. We find that the spin-spin interaction between the angular momentum of the black hole and the swirling of the background leads to new interesting effects as it breaks the symmetry between the upper and lower hemispheres. One of the new features of the spin-spin interaction is the existence of up to three light rings for suitable choices of the angular momentum parameter a and swirling parameter j. In comparison to the Schwarzschild black hole immersed in a swirling universe, the light rings typically all possess different radii.
Capobianco et al. (Thu,) studied this question.