Shadow of a Schwarzschild black hole surrounded by a Bach-Weyl ring

Understand

We have studied the shadows of a Schwarzschild black hole surrounded by a Bach-Weyl ring through the backward ray-tracing method.

• The presence of Bach-Weyl ring leads to that the photon dynamical system is non-integrable and then chaos would appear in the photon motion, which affects sharply the black hole shadow.
• The size and shape the black hole shadow depend on the black hole parameter, the Bach-Weyl ring mass and the Weyl radius between black hole and ring.
• Some self-similar fractal structures also appear in the black hole shadow, which originates from the chaotic lensing.