Black Hole Glimmer Signatures of Mass, Spin, and Inclination

Understand

Gravitational lensing near a black hole is strong enough that light rays can circle the event horizon multiple times.

• Photons emitted in multiple directions at a single event, perhaps because of localized, impulsive heating of accreting plasma, take multiple paths to a distant observer.
• In the Kerr geometry, each path is associated with a distinct light travel time and a distinct arrival location in the image plane, producing black hole glimmer.
• This sequence of arrival times and locations uniquely encodes the mass and spin of the black hole and can be understood in terms of properties of bound photon orbits.