Shadow of axisymmetric, stationary, and asymptotically flat black holes in the presence of plasma

We study the shadow produced by a class of rotating black holes surrounded plasma. The metric for these arises applying Newman-Janis algorithm to family spherically symmetric spacetimes, which includes several well known geometries as special cases. derive general expression shape in case that plasma frequency leads separable Hamilton-Jacobi equation light. present two examples we obtain contours and observables resulting from them. In one, analyze Kerr-Newman-like geometries, including braneworld Horndeski gravity holes, while other, consider scalar-tensor 4D Einstein-Gauss-Bonnet spacetimes. both cases, find presence smaller less deformed shadow.