Related papers: Scalar absorption: Black holes versus wormholes
A massless field propagating on spherically symmetric black hole metrics such as the Schwarzschild, Reissner-Nordstr\"{o}m and Reissner-Nordstr\"{o}m-de Sitter backgrounds is considered. In particular, explicit formulae in terms of…
Black-hole spectroscopy aims to infer the fundamental properties of black holes by analysing the spectrum of gravitational waves emitted as they settle into equilibrium. These resonances, known as quasinormal modes (QNMs), decay rapidly,…
The Schwarzschild spacetime is for electromagnetic waves like a nonuniform medium with a varying refraction index. A fraction of an outgoing radiation scatters off the curvature of the geometry and can be intercepted by a gravitational…
We study to what extent wormholes can mimic the observational features of black holes. It is surprisingly found that many features that could be thought of as ``characteristic'' of a black hole (endowed with an event horizon) can be closely…
We compute precise values of quasinormal modes of a massive scalar field in the background of the Schwarzschild-like brane-localised black holes. It is shown that the quasinormal spectrum of the massive field differs qualitatively from that…
The merger of binary black holes produces a series of decaying oscillations, during which energy is radiated in gravitational waves. The characteristic signal in the ringdown phase can be described by complex oscillation frequencies called…
Here we propose a simple explanation why echoes from wormholes mimicking black holes may be so small that they cannot be observed. The essence of the effect is in the redistribution of the initial energy of gravitational wave among multiple…
Johannsen metric is a natural and significant generalization of the Kerr metric, representing the most general stationary, axisymmetric spacetime that preserves the Carter constant of motion. The theoretical status furnishes a powerful,…
We investigate the scattering of electromagnetic and gravitational waves off a Reissner-Nordstr\"om black hole in the low-temperature regime where the near-horizon throat experiences large quantum fluctuations. We find that the black hole…
We study the absorption of scalar fields by extreme/exotic compact objects (ECOs) -- horizonless alternatives to black holes -- via a simple model in which dissipative mechanisms are encapsulated in a single parameter. Trapped modes,…
We first present an overview of the Schwarzschild vacuum spacetime within general relativity, with particular emphasis on the role of scalar polynomial invariants and the null frame approach (and the related Cartan invariants), that…
By combining the numerical solution of the nonlinear hydrodynamics equations with the solution of the linear inhomogeneous Zerilli-Moncrief and Regge-Wheeler equations we investigate the properties of the gravitational radiation emitted…
Assuming that general relativity is the correct theory of gravity in the strong field limit, can gravitational wave observations distinguish between black hole and other compact object sources? Alternatively, can gravitational wave…
The recent reported gravitational wave detection motivates one to investigate the properties of different black hole models, especially their behavior under (axial) gravitational perturbation. Here, we study the quasinormal modes of black…
We study the absorption and scattering of massless scalar waves propagating in spherically symmetric spacetimes with dynamical cosmological constant both in low-energy and high-energy zones. In the former low-energy regime, we solve…
We analyze the scattering of a planar monochromatic electromagnetic wave incident upon a Schwarzschild black hole. We obtain accurate numerical results from the partial wave method for the electromagnetic scattering cross section, and show…
We test the stability of various wormholes and black holes supported by a scalar field with a negative kinetic term. The general axial perturbations and the monopole type of polar perturbations are considered in the linear approximation.…
Black-hole spectroscopy is a powerful tool to probe the Kerr nature of astrophysical compact objects and their environment. The observation of multiple ringdown modes in gravitational waveforms could soon lead to high-precision…
We compare the optical appearance of a thin accretion disk in the Simpson-Visser spacetime to the Schwarzschild black hole case in this paper. We calculate and illustrate the red-shift and observed flux distributions as viewed by distant…
The Klein-Gordon equation for the wave function of a single massive scalar is written in spherical and parabolic coordinates in the presence of a Schwarzschild background, and some semi-classical techniques for deriving asymptotic results…