We perform the first nonlinear and self-consistent study of the merger and ringdown of a
black hole mimicking object with stable light rings. To that end, we numerically solve the full …

Recent investigations of the pseudospectrum in black hole spacetimes have shown that
quasinormal mode frequencies suffer from spectral instabilities. This phenomenon may …

This investigation delves into the ringdown signals produced by semiclassical stars, which
are ultra-compact, regular solutions of the Einstein equations incorporating stress-energy …

Black hole echo is an important observable that can help us better understand gravitational
theories. The non-linear electrodynamic black holes can admit multi-horizon, and the …

One of the main predictions of general relativity is the existence of black holes featuring a
horizon beyond which nothing can escape. Gravitational waves from the remnants of …

Postmerger gravitational wave echoes provide a unique opportunity to probe the near-
horizon structure of astrophysical black holes, which may be modified due to …

Quantum black holes, a broad class of objects that refine the solutions of general relativity by
incorporating semiclassical and/or quantum gravitational effects, have recently attracted …

In the context of Einstein-Maxwell-scalar theory with a nonminimal coupling between the
electromagnetic and scalar field, we study linear (non) radial perturbations and nonlinear …

The study of regular black holes and black hole mimickers as alternatives to standard black
holes has recently gained significant attention, driven both by the need to extend general …

Spacetime singularities are a generic prediction of general relativity. They are believed to
mark the breakdown of the theory and, for this reason, they represent one of the main drivers …