We study quasinormal modes (QNMs) in 5D electrically charged Bardeen black holes spacetime by considering the scalar and electromagnetic field perturbations. The black holes spacetime is an exact solution of Einstein gravity coupled to nonlinear electrodynamics in five dimensions, which has nonsingular behavior. To calculate QNMs, we use the WKB approximation method up to sixth order. Due to the presence of electric charge $q_e > 0$, both the scalar and electromagnetic field perturbations decay more slowly when compared to the Schwarzschild-Tangherlini black holes. We discover that the scalar field perturbations oscillate more rapidly when compared to the electromagnetic field perturbations. In terms of damping, the scalar field perturbations damp more quickly. Graphically we show that the transmission (reflection) coefficients decrease (increase) with an increase in the magnitude of the electric charge $q_e$. The emission of gravitational waves allows spacetime to undergo damped oscillations due to the nonzero value of the imaginary part, which is always negative. The imaginary part of the QNMs frequencies is continuously decreasing with an increase in the magnitude of the electric charge $q_e$ for a given mode ($l,n$). A connection between the QNMs frequencies and the black hole shadow, as well as the geometric cross-section in the eikonal limit, is also described.
We study scalar perturbations for a four-dimensional asymptotically Lifshitz black hole in conformal gravity with dynamical exponent z=0, and spherical topology for the transverse section, and we find analytically and numerically the quasinormal modes for scalar fields for some special cases. Then, we study the stability of these black holes under scalar field perturbations and the greybody factors.
It is shown that the paper "Greybody radiation and quasinormal modes of Kerr-like black hole in Bumblebee gravity model", Eur. Phys. J. C 81, 501 (2021). arXiv:2102.06303, recently published in this journal is based on an incorrect result obtained by Ding et al., Eur. Phys. J. C 80, 178 (2020). arXiv:1910.02674, for a Kerr-like black hole solution.
In this paper, the greybody factor is studied analytically for a rotating regular Bardeen black hole surrounded by perfect fluid dark matter. Firstly, we examine the behavior of effective potential by using the radial equation of motion developed from the Klein-Gordon equation. We then consider tortoise coordinate to convert the radial equation into Schrödinger form equation. We solve the radial equation of motion and obtain two different asymptotic solutions in terms of hypergeometric function measured at distinct regimes so called near and far-field horizons. These solutions are smoothly mat…
In this paper, we formulate an analytical expression of greybody factor in the context of rotating Bardeen black hole which is valid in low energy and low angular momentum region. Primarily, we analyze the profile of effective potential which originates the absorption probability. We then derive two asymptotic solutions by solving the radial part of Klein-Gordon equation in two different regions, namely, black hole and far-field horizons. We match these solutions smoothly to an intermediate regime to extend our results over the whole radial coordinate. In order to elaborate on the significance…
We study the propagation of a probe massless nonminimally coupled scalar field in a fixed gravitational background of a cloud of strings in (2+1) dimensions. We obtain exact analytical expressions for the reflection coefficient, the absorption cross section, the decay rate as well as the quasinormal frequencies. The impact of the nonminimal coupling is investigated in detail. Our results show that Universality is not respected in general, and that scalar perturbations are stable.
We find the low lying quasinormal mode frequencies of the recently proposed novel four dimensional Gauss-Bonnet de Sitter black holes for scalar, electromagnetic and Dirac field perturbations using the third order WKB approximation as well as Padé approximation, as an improvement over WKB. We figure out the effect of the Gauss-Bonnet coupling $α$ and the cosmological constant $Λ$ on the real and imaginary parts of the QNM frequencies. We also study the greybody factors and eikonal limits in the above background for all three different types of perturbations.
Bardeen de-Sitter (BdS) black hole is a spherically symmetric solution of Einstein's equation which is coupled to nonlinear electromagnetic field in a way that one gets a regular solution, devoid of any singularity at the origin. We compute the quasinormal (QN) frequencies for BdS black hole due to electromagnetic and gravitational perturbations. We analyse the behaviour of both real and imaginary parts of BdS QN frequencies by varying the black hole parameters and compare frequencies with Reissner-Nordström de-Sitter (RN-dS) black hole. Interestingly, we find that the response of BdS and RN-d…
In this paper we have studied the propagation of a massless scalar field minimally coupled to a black hole with the source of cloud of strings in $2+1$ $f(R)$gravity theory. In particular we have found analytical results for the decay rate, reflection coefficient, greybody factors, as well as the black hole temperature. On the other hand, our quasinormal modes analyses reveals stability in the propagation of a massless scalar field in the cloud of strings black hole spacetime. However, under a suitable choose of parameters an instability is found. Furthermore based on the Bekenstein conjecture…
Gravitational decoupling can add hair to the black holes by adding extra sources. The quasinormal modes of hairy black hole caused by gravitational decoupling for the massless scalar field, electromagnetic field, and gravitational perturbation are investigated. The equations of effective potential for three perturbations are derived in hairy black hole spacetime. We also study the time evolution corresponding to the three perturbations, and the quasinormal mode frequencies are calculated using the Prony method through the time-domain profiles. By analyzing the influence of the hairs ($α$, $l_0…
Perturbations of black holes with primary hair: time evolutions, quasinormal modes and greybody factors
CEICO, Institute of Physics of the Czech Academy of Sciences（捷克科学院物理研究所）；CENTRA, Departamento de Física, Instituto Superior Técnico - IST, Universidade de Lisboa - UL（里斯本大学技术学院物理系CENTRA）
In our recent study Ref. [1]: Eur. Phys. J. C 81, 501 (2021) , the main goal was to reveal the Lorentz symmetry breaking (LSB) effect in the rotating black holes via the greybody factor and quasinormal mode analyzes. Ding et al. [2] Kerr-like black hole solution of the bumblebee gravity model used in our paper [1] has unquestionably proven by Maluf and Muniz [3] that it is wrong. We now explain under which condition the greybody factor and quasinormal mode analyzes performed in [1] become valid. We re-make the calculations according to the condition in question and present the new results in t…
We discuss the phenomenology of massless scalar fields around a regular Bardeen black hole, namely absorption cross section, scattering cross section and quasinormal modes. We compare the Bardeen and Reissner-Nordström black holes, showing limiting cases for which their properties are similar.
In the framework of the Lorentz symmetry breaking (LSB), we investigate the quasinormal modes (QNMs) and the greybody factors (GFs) of the Kerr-like black hole spacetime obtained from the bumblebee gravity model. In particular, we analyze the scalar and fermionic perturbations of the black hole within the framework of both semi-analytic WKB method and the time domain approach. The impacts of the LSB on the bosonic/fermionic QNMs and GFs of the Kerr-like black hole are investigated in detail. The obtained results are graphically depicted and discussed.
We investigate quasinormal modes, greybody factor, and Hawking evaporation of a five-dimensional Kerr-anti de Sitter (AdS$_5$) black hole by solving a wave equation for a test massive scalar field in terms of the local Heun function. We clarify the distribution of the quasinormal modes satisfying the ingoing and decaying boundary conditions at the event horizon and conformal infinity, respectively, and their splitting behaviors in the complex frequency plane with respect to a variation of spin parameters. We also point out the existence of purely imaginary modes. Further, we develop a method t…
The exact solutions of the Dirac equation that describe a massive, non-charged particle with spin-(1/2) in the curved spacetime geometry of regular Bardeen black hole surrounded by quintessence (BBHSQ) are investigated. We first derive the Dirac equation in the BBHSQ background using a null tetrad in the Newman-Penrose formalism. Afterward, we separate the Dirac equation into ordinary differential equations for the radial and angular parts. The angular equations are solved exactly in terms of standard spherical harmonics. The radial part equations are transformed into a Schrödinger like differ…
In this paper we investigate gravitational perturbations of a regular black hole, particularly Bardeen solution. Such system is solution of Einstein equations that do not have a singularity at the origin of the radial symmetry. However it still have events horizons depending on the values of the characteristic parameters of the solution. When a black hole is perturbed, it oscillates. It gives rise to damped vibrating modes which are known as quasinormal modes. It is calculated the quasinormal frequencies of a regular black hole using the third order WKB approximation for gravitational perturba…
The purpose of this paper is to study quasinormal modes (QNM) of the Bardeen black hole due to scalar perturbations. We have done a thorough analysis of the QNM frequencies by varying the charge $q$, mass $M$ and the spherical harmonic index $l$. The unstable null geodesics are used to compute the QNM's in the eikonal limit. Furthermore, massive scalar field modes are also studied by varying the mass of the field. Comparisons are done with the QNM frequencies of the Reissner-Nordstrom black hole.
In this work, we investigate the quasinormal frequencies of a class of regular black hole solutions which generalize Bardeen and Hayward spacetimes. In particular, we analyze scalar, vector and gravitational perturbations of the black hole both with the semianalytic WKB method and their time-domain profiles. We analyze in detail the behavior of the spectrum depending on the parameter $p/q$ of the black hole, the quantum number of angular momentum and the $s$ number. In addition, we compare our results with the classical solution valid for $p = q = 1$.
Accretion, greybody factor, quasinormal modes, power spectrum, sparsity of Hawking radiation, and weak gravitational lensing of a minimum measurable length inspired Schwarzchild black hole
Motivated by recent work on the Modified Maxwell (ModMax) black holes [Phys.Lett.B 10.1016/j.physletb.2020.136011], which are invariant in duality rotations and conformal transformations founded in [ Phys.Rev.D 10.1103/PhysRevD.102.121703], we probe its effects on the shadow cast, weak field gravitational lensing, and neutrino propagation in its vicinity. Using the EHT data for the shadow diameter of Sgr. A* and M87*, and LIGO/VIRGO experiments for the dyonic ModMax black hole perturbations, we find constraints for ModMax parameters such as $Q_\text{m}$ and the screening factor $γ$. We also an…
In this paper, we discuss the effects of nonlinear electrodynamics (NED) on non-rotating black holes, parametrized by the field coupling parameter $β$ and magnetic charge parameter $P$ in detail. Particularly, we survey physical properties of the magnetically charged black hole, thermodynamic properties, observational appearance, quasinormal modes and absorption cross sections. We then show that the black hole gets colder with increasing charge. Investigating the heat capacity, we see that the black hole is thermally stable, which is amplified by introduction of a generalized uncertainty princ…
Parametrized quasinormal modes, greybody factors and their correspondence
CENTRA, Departamento de Física, Instituto Superior Técnico - IST, Universidade de Lisboa - UL（里斯本大学高等技术学院物理系CENTRA）；Dipartimento di Fisica, “Sapienza” Universitá di Roma（罗马第一大学物理系）；Sezione INFN Roma1（意大利国家核物理研究所罗马一分部）
Quasinormal modes and greybody factors of magnetically charged de Sitter black holes probed by massless external fields in Einstein Euler Heisenberg gravity
We give explicit expressions for the finite frequency greybody factor, quasinormal modes and Love numbers of Kerr black holes by computing the exact connection coefficients of the radial and angular parts of the Teukolsky equation. This is obtained by solving the connection problem of the confluent Heun equation in terms of the explicit expression of irregular Virasoro conformal blocks as sums over partitions via the AGT correspondence. In the relevant approximation limits our results are in agreement with existing literature. The method we use can be extended to solve the linearized Einstein …
So far the study of black hole perturbations has been mostly focussed upon the classical black holes with singularities at the origin and hidden by event horizon. Compared to that, the regular black holes are a completely new class of solutions arising out of modification of general theory of relativity by coupling gravity to an external form of matter. Therefore it is extremely important to study the behaviour of such regular black holes under different types of perturbations. Recently a new regular Bardeen black hole solution with a de Sitter branch has been proposed by Fernando. We compute …
In this article, we study the particle dynamics around a static and spherically symmetric Bardeen-Kiselev black hole (BK BH) which is a solution of the Einstein-non-linear Maxwell field equations along with a quintessential field. We discuss its essential geometrical properties such as scalar invariants and size of innermost stable circular orbits. Dynamics of test particles around the BH is also studied. Moreover, we also computed the fundamental frequencies of a test particle orbiting the BH in a slightly perturbed orbit. Further, the degeneracy relations between the spin of rotating Kerr BH…
We give a pedagogical introduction to black holes (BHs) greybody factors (GFs) and quasinormal modes (QNMs) and share the recent developments on those subjects. In this study, our primary focus will be on the bosonic and fermionic GFs and QNMs of various BH and brane geometries and reveal the fingerprints of the invisibles with the radiation spectra to be obtained by the WKB approximation and bounding the Bogoliubov coefficients (together with the Miller-Good transformation) methods. (*Due to the notification of arXiv "The Abstract field cannot be longer than 1,920 characters", the appeared Ab…
In this paper, we investigate the shadow radius and quasinormal modes of a four-dimensional magnetically charged Einstein-Gauss-Bonnet Bardeen black hole and point out a simple connection between them in the eikonal limit. By studying a massless scalar field perturbation in this spacetime background and using the sixth-order Wentzel-Kramers-Brillouin(WKB) approximation, we get the quasinormal modes(QNMs) and perform a detailed analysis. It shows that the quasinormal modes are depend on the Gauss-Bonnet coupling constant and the magnetic charge. We also give a formula of the QNMs and shadow rad…
