Distinguishing gravitational and emission physics in black-hole imaging: spherical symmetry

Understand

Imaging a supermassive black hole and extracting physical information requires good knowledge of both the gravitational and the astrophysical conditions near the black hole.

• When the geometrical properties of the black hole are well understood, extracting information on the emission properties is possible.
• Similarly, when the emission properties are well understood, extracting information on the black-hole geometry is possible.
• At present however, uncertainties are present both in the geometry and in the emission, and this inevitably leads to degeneracies in the interpretation of the observations.