Echoes from backreacting exotic compact objects

Understand

The possible detection of echoes in late gravitational-wave signals is the most promising way to test horizonless alternatives to general relativistic black holes, and probe the physics of these hypothetical ultra-compact objects.

• While there is currently no evidence for the presence of such signatures, better accuracy is expected with the growing wealth of data from gravitational waves observatories.
• So far, several searches for these specific signals have been performed considering equidistant intervals between consecutive echoes, i.e.
• quasi-periodic wave-forms, and ignoring possible backreaction effects of the incoming waves.