Article
Astronomy & Astrophysics
Wen-Di Guo, Qin Tan, Yu-Xiao Liu
Summary: This paper investigates the quasinormal modes of a charged black hole with scalar hair, obtaining the fundamental frequencies numerically and studying the effect of magnetic charge on the modes.
Article
Astronomy & Astrophysics
Wen-Di Guo, Qin Tan
Summary: In this paper, a singularity-free topology star/black hole is constructed based on the five-dimensional Einstein-Maxwell theory. After performing the Kaluza-Klein reduction, an effective four-dimensional spherically static charged black hole with scalar hair is obtained. The study focuses on the quasinormal modes of the scalar, electromagnetic, and gravitational fields in the background of this effective four-dimensional charged black hole. The QNM frequencies are obtained semianalytically using the asymptotic iteration method and show good agreement with other approximation methods.
Article
Physics, Particles & Fields
Ramon Becar, P. A. Gonzalez, Yerko Vasquez
Summary: We analyze the stability of a charged massive scalar field propagating in the background of a four-dimensional Ernst black hole by studying its quasinormal modes (QNMs). The QNMs are calculated using both the semi-analytical Wentzel-Kramers-Brillouin method and the continued fraction method. It is found that the decay rate of the QNMs decreases with increasing harmonic angular number l for a scalar field mass less than a critical mass, while the behavior is reversed for a scalar field mass greater than the critical mass, with the longest-lived modes corresponding to the lowest angular number.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Guoyang Fu, Dan Zhang, Peng Liu, Xiao-Mei Kuang, Qiyuan Pan, Jian-Pin Wu
Summary: We investigate the scalar field system over a charged Weyl black hole characterized by a parameter lambda. We find that the imaginary part of the quasinormal mode spectra is always negative, indicating the stability of the system under scalar field perturbation. Additionally, both the quasinormal mode spectra and Hawking radiation exhibit qualitatively similar characteristics, increasing with rising lambda and approaching a constant for large lambda. Notably, the ringing tail shows an exponential decay as lambda increases, suggesting a detectable imprint on the ringing tail by future observations.
Article
Astronomy & Astrophysics
Zhen Li
Summary: Black holes serve as a natural laboratory for the study of particle physics and astrophysics. This study focuses on a newly proposed rotating regular black hole and investigates the behavior of a massive scalar field near it. The research examines how this nonsingular spacetime affects the superradiance instability and quasinormal modes of the scalar field. The results show excellent agreement with previous research in the Kerr limit and provide insights into the effects of black hole spin, regularity, and scalar field mass on the quasinormal modes.
Article
Astronomy & Astrophysics
Keitaro Tomikawa, Tsutomu Kobayashi
Summary: In this study, we investigate odd parity perturbations of spherically symmetric black holes with time-dependent scalar hair in shift-symmetric higher-order scalar-tensor theories without assuming degeneracy conditions. By analyzing the general form of the quadratic Lagrangian and refining the stability conditions, we obtain insights into the behavior of these perturbations. This research also extends to include the matter energy-momentum tensor as a source term, providing a more comprehensive understanding of the dynamics involved.
Article
Astronomy & Astrophysics
Edgardo Franzin, Stefano Liberati, Jacopo Mazza, Ramit Dey, Sumanta Chakraborty
Summary: This study investigates scalar test-field perturbations on a Kerr-black-bounce background, exploring rotating regular black holes and/or rotating traversable wormholes. The research confirms the stability of regular black holes and identifies a set of growing modes that render traversable wormholes unstable.
Article
Astronomy & Astrophysics
A. Martinez-Merino, M. Sabido
Summary: In this study, the lowest value of black hole spin is investigated using non-extensive entropies. The results show that the spin depends on the area and non-extensive parameter, with the modification only present for micro black holes.
Article
Astronomy & Astrophysics
Pedro Henrique Croti Siqueira, Mauricio Richartz
Summary: In this article, we use the continued fraction method to determine the eigenfrequencies of a scalar field around a Kerr-like black hole and explore the effects of a deformation parameter on the quasinormal modes and quasibound states. We calculate the timescales associated with the superradiant instabilities of the scalar field and discuss the properties of stationary scalar clouds that may be formed by these instabilities.
Article
Astronomy & Astrophysics
Omar Pedraza, L. A. Lopez, R. Arceo, I Cabrera-Munguia
Summary: This paper investigates the quasinormal modes for scalar, electromagnetic, and gravitational axial perturbations in the Hayward regular black hole surrounded by quintessence (HBH-omega(q)) using the third-order WKB approximation. The dependence of the quasinormal modes on the parameters of the regular black hole and the test fields is determined, and the greybody factor is calculated through numerical analysis to give transmission and reflection coefficients for the scattered wave.
MODERN PHYSICS LETTERS A
(2022)
Article
Physics, Multidisciplinary
L. A. Lopez, Valeria Ramirez
Summary: In this contribution, the quasi-normal modes of a regular black hole with a magnetic charge in nonlinear electrodynamics are studied, considering scalar and electromagnetic perturbations. The Generic-class, which includes the Bardeen-class, Hayward-class, and New-class solutions, can represent a black hole with two horizons or one horizon. First, the critical values of the magnetic charge and mass are obtained; Then, using the third-order WKB approximation, the dependence of the quasi-normal modes on the parameters of the Generic-class is determined. Finally, the transmission and reflection coefficients of the scattered wave in the third-order WKB approximation are calculated.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Physics, Multidisciplinary
R. T. Cavalcanti, R. C. de Paiva, R. da Rocha
Summary: The behavior of hairy black hole solutions obtained by the gravitational decoupling method under scalar perturbations is investigated. Numerical simulations are conducted to obtain wave solutions for various values of GD hairy black hole parameters, and it is found that higher-frequency modes are highly sensitive to these parameters. A comparison with the Schwarzschild solution reveals the unique physical characteristics of GD hairy black holes.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Multidisciplinary Sciences
J. A. Campos, M. A. Anacleto, F. A. Brito, E. Passos
Summary: This paper investigates the quasinormal modes for a scalar field around a noncommutative Schwarzschild black hole, and verifies the effect of noncommutativity on quasinormal frequencies using two widely used methods. It is found that the shadow radius decreases as the noncommutative parameter increases, and the shadow radius is nonzero even at the zero mass limit for finite noncommutative parameter.
SCIENTIFIC REPORTS
(2022)
Article
Physics, Particles & Fields
Yu-Ping An, Li Li
Summary: We have proven the absence of charged scalar hair for static black holes in de-Sitter spacetime between the event horizon and the cosmological horizon. The proof is not dependent on the assumption of spherical symmetry and allows for general non-minimal coupling functions and higher curvature term corrections. This result has implications for the possibility of spontaneous scalarization around charged de-Sitter black holes.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Saulo Albuquerque, Iarley P. Lobo, Valdir B. Bezerra
Summary: In this study, perturbations of the massless Dirac field in the background of a black hole solution were analyzed using a polymerization technique inspired by loop quantum gravity (LQG) Theory. The quasinormal modes of several modes, multipole numbers, and two classes of black holes were examined using the sixth order WKB method. The potential governing these perturbations was also considered to analyze the bound on the greybody factor (GF) resulting from particle emission rates. The results show that the LQG parameters raise the potential and the real and imaginary parts of the quasinormal frequencies, and decrease the bound on the GF for the two classes of black holes (with more prominent effects for the de-amplification case, which is consistent with previous analyses for other fields).
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Avijit Chowdhury, Narayan Banerjee
GENERAL RELATIVITY AND GRAVITATION
(2019)
Article
Physics, Particles & Fields
Avijit Chowdhury
EUROPEAN PHYSICAL JOURNAL C
(2019)
Article
Astronomy & Astrophysics
Avijit Chowdhury, Narayan Banerjee
Article
Multidisciplinary Sciences
Avijit Chowdhury, Semin Xavier, S. Shankaranarayanan
Summary: Motivations for modified gravity have grown in the last two decades, both at theoretical and observational levels. While f(R) and Chern-Simons gravity have received more attention as simpler generalizations, they lack other modes present in modified theories of gravity. In contrast, quadratic gravity (Stelle gravity) is a more general second-order modification that includes a massive spin-2 mode. Through the study of gravitational wave energy-flux and backreaction on the spacetime of black holes, it has been demonstrated that the massive spin-2 mode carries more energy than the spin-0 mode. These effects are particularly pronounced for intermediate-mass black holes, making them important targets for LISA.
SCIENTIFIC REPORTS
(2023)
Article
Astronomy & Astrophysics
Avijit Chowdhury, Saraswati Devi, Sayan Chakrabarti
Summary: We study the stability and response of a naked singularity spacetime in the four-dimensional Einstein-Gauss-Bonnet (EGB) gravity. By investigating perturbations from scalar, electromagnetic, and Dirac fields, we observe that as the coupling constant increases, the echoes align and the quasinormal mode structure of the 4D-EGB naked singularity-spacetime becomes prominent.
Article
Astronomy & Astrophysics
Avijit Chowdhury, Narayan Banerjee
