Resonances, black hole mimickers and the greenhouse effect: consequences for gravitational-wave physics

Understand

Ultracompact objects with photonspheres are known to mimic many observational features of black holes.

• It has been suggested that anomalous tidal heating or the presence of resonances in gravitational wave signals would be a clear imprint of a surface or absence of a horizon.
• Such claims and studies are all based on a frequency-domain analysis, assuming stationarity.
• Here we show that the object needs to first "fuel-up" until it reaches the stationary regime.