Shadow of a disformal Kerr black hole in quadratic DHOST theories

Understand

We have studied the shadow of a disformal Kerr black hole with an extra deformation parameter, which belongs to non-stealth rotating solutions in quadratic Degenerate Higher Order Scalar Tensor (DHOST) theory.

• Our result show that the size of the shadow increases with the deformation parameter for the black hole with arbitrary spin parameter.
• However, the effect of the deformation parameter on the shadow shape depends heavily on the spin parameter of black hole and the sign of the deformation parameter.
• The change of the shadow shape becomes more distinct for the black hole with the more quickly rotation and the more negative deformation parameter.