Related papers: Ringdown and echoes from compact objects: Debye se…
We construct compact and high accuracy Reduced Basis (RB) representations of single and multiple quasinormal modes (QNMs). The RB method determines a hierarchical and relatively small set of the most relevant waveforms. We find that the…
Black hole (BH) perturbation is followed by a ringdown phase which is dominated by quasinormal modes (QNM). These modes may provide key signature of the gravitational waves. The presence of a deformed spacetime structure may distort this…
In black hole perturbation formalism, the gravitational waveform is obtained by the convolution of the Green's function and the source term causing radiation emission. Hence, the ringdown properties, namely its start time, depend on both…
Quasinormal modes describe the return to equilibrium of a perturbed system, in particular the ringdown phase of a black hole merger. But as globally-defined quantities, the quasinormal spectrum can be highly sensitive to global structure,…
Quasinormal modes (QNMs) are usually characterized by their time dependence; oscillations at specific frequencies predicted by black hole (BH) perturbation theory. QNMs are routinely identified in the ringdown of numerical relativity…
This work investigates the echoes in axial gravitational perturbations in compact objects. To this end, we propose an alternative scheme of the finite difference method implemented in two coordinate systems, where the initial conditions are…
The recent convergence of gravitational-wave (GW) observations and black hole imaging provides complementary probes of strong-gravity dynamics. While the black hole shadow is typically modeled as a static feature, a dynamically perturbed…
We develop a quantum optical framework for probing black hole quasinormal modes (QNMs) using two-level atoms in the spirit of the horizon-brightened acceleration radiation (HBAR) program. Starting from the QNM contribution to the Wightman…
Gravitational waves from binary coalescences provide one of the cleanest signatures of the nature of compact objects. It has been recently argued that the post-merger ringdown waveform of exotic ultracompact objects is initially identical…
We present an analytical and numerical investigation of the quasinormal excitation factors of ultracompact horizonless objects. These systems possess long lived quasinormal modes with extremely small imaginary parts, originating from the…
This paper investigates the quasinormal mode (QNM) vibrations of a rotating cylindrical black hole (or black string) spacetime that is surrounded by a thin shell rotating synchronously with the black string's axis. The existence of the thin…
The quasinormal mode spectrum of black holes plays a crucial role in the modelling of post-merger ringdown signals. However, the spectrum is extremely sensitive to small deformations of the system and describes the linear response only in a…
Full-wave numerical methods based on quasinormal modes (QNMs) offer valuable physical insights and computational efficiency for analyzing electromagnetic resonators. However, despite their advantages, many researchers in electromagnetism…
We study the dynamical excitation of quasinormal modes (QNMs) through the plunge, merger and ringdown of an extreme-mass-ratio-inspiral into a Schwarzschild black hole, for generic orbital configurations. We work out the QNM causality…
We present a fully Bayesian, data-driven framework for identifying quasinormal modes in high-accuracy Cauchy-Characteristic Evolution (CCE) gravitational waveforms. Applying this to a public catalog, we identify QNM overtones, retrograde…
A generic feature of nearly out-of-equilibrium dissipative systems is that they resonate through a set of quasinormal modes. Black holes - the absorbing objects par excellence - are no exception. When formed in a merger, black holes vibrate…
We investigate the possibility of using quasi-normal modes (QNMs) to probe the microscopic structure of two-dimensional (2D) anti-de Sitter (AdS$_2$) dilatonic black holes. We first extend previous results on the QNMs spectrum, found for…
We investigate the scalar-wave resonances of systems composed of identical Neumann-type inclusions arranged periodically around a circular ring. Drawing on natural similarities with the undamped Rayleigh-Bloch waves supported by infinite…
Closed-form expressions for the ringdown complex amplitudes of nonspinning unequal-mass binaries in arbitrarily eccentric orbits are presented. They are built upon 237 numerical simulations contained within the RIT catalog, through the…
This work presents a new design for broadband absorption of low-frequency acoustic waves using a thin coating made of subwavelength acoustic resonators arranged periodically on a reflective surface. We first study the associated scattering…