Image of a Black Hole Illuminated by a Parabolic Screen

An analytical model of a parabolic screen illuminating a black hole is proposed. This allows to avoid naturally the appearance of edge effects associated with photons moving along the plane of the screen illuminating the black hole. The temperature distribution along the radius of the screen corresponds to that for a relativistic disk (Novikov–Thorne disk). It is shown that the structure of the emerging black hole shadow differs significantly from the case when the photon source is a remote screen, since in the model considered, the photons subjected to strong gravitational lensing of the black hole are emitted by the “back side” of the screen, which would not be visible in the absence of a black hole. In the thin screen approximation, the shadow of a Schwarzschild black hole has been constructed in cases when the angle between the axis of symmetry of the illuminating screen and the direction towards the observer is 5°, 30°, 60°, and 80°. The images for the Kerr black hole are shown for the angles of 60° and 80°.