Exotic compact objects: ergoregion instability, ringdown and echoes
Presenting author: Elisa Maggio
Gravitational waves allow to understand the nature of compact objects, potentially probing microscopic corrections at the horizon scale of black holes. Some models of exotic compact objects replace the event horizon by a reflective surface. Spinning horizonless compact objects may be unstable against an ergoregion instability when spinning sufficiently fast. We analyse the ergoregion instability and its astrophysical impact for the viability of exotic compact objects. We show that an absorption rate of 60% at the surface would quench the instability for any spin. Finally, we present an analytical gravitational-wave template describing the ringdown and the echoes of a spinning ultracompact object. The template can be easily implemented in a matched-filter based search for echoes.
Oral presentation: yes. Poster: no.