Boltzmann Meets Lorentz: A Surrogate Model for Black Hole Echoes

Understand

The existence of black hole horizons has not been strictly proven observationally, and indeed it may not be possible to do so.

• However, alternatives may be established by the observation of gravitational wave echoes that probe possible near-horizon structure.
• These echoes are proposed to be generated in exotic compact objects that are horizonless and feature a partially reflecting "wall" inside their light rings, creating a cavity in which gravitational perturbations may echo, while leaking out through the angular momentum barrier with each pass.
• The characteristic signature of echoes is a comb of nearly evenly spaced spectral resonances.