Hawking radiation from a rotating acoustic black hole

Using the new global embedding approach and analytical continuation method of wave function we discuss Hawking radiation of acoustic black holes. Unruh–Hawking temperature of the acoustic black hole is derived. The corresponding relation between these methods calculating Hawking radiation of acoustic black hole is established. The calculation result shows that the contributions of chemical potential to the ingoing wave and the outgoing wave are the same.     

Magnetic support near a charged rotating black hole

Three equilibrium conditions for magnetic trapping are applied to a charged black hole whose axis of rotation is aligned with an asymptotically uniform weak magnetic field.     

Radiation spectrum of a high-dimensional rotating black hole

This study extends the classical Damour-Ruffini method and discusses Hawking radiation in a (n + 4)-dimensional rotating black hole. Under the condition that the total energy and angular momentum of spacetime are conservative, but angular momentum a = J/M of unit mass of the black hole is variable, taking into consideration the reaction of the radiation of the particle to the spacetime, a new Tortoise coordinate transformation and discuss the black hole radiation spectrum is discussed. The radiation spectru...     

Stationary electromagnetic fields around a rotating black hole

The general stationary solution of Maxwell's equations in the Kerr background geometry is given. Future applications are outlined.     

Exploring the shadow of a rotating charged ModMax black hole

The research presented in this paper discusses the impact that the parameters of charge(Q) and screening factor(γ) have on properties of the horizon and silhouette of rotating charged Mod Max black holes which were reviewed in [Eur. Phys. J. C(2022) 82:1155] recently, building upon previous findings in the field. Furthermore, the study explores the behavior of null geodesics, which can help us better understand the apparent shape of the black hole’s silhouette,as well as the distortion parameter...     

Scalar fields around a charged,rotating black hole

The scalar wave equation is separated in a Kerr-Newman geometry and some properties of the effective potential barrier are discussed. Stationary solutions for massless scalar fields are found explicitly.For the most part, this work was carried out in 1973, while Z. S. and M. . were students at the Faculty of Mathematics and Physics. At present, Z. S. is at the Department of Physics, The School of Mines, Ostrava, M. . — at the Institute of Physical Metallurgy, Brno.     

Stationary axially symmetric perturbations of a rotating black hole

A stationary axially symmetric perturbation of a rotating black hole due to a distribution of test matter is investigated. The Newman-Penrose spin coefficient formalism is used to derive a general set of equations describing the perturbed space-time. In a linear approximation we show that the mass and angular momentum of a rotating black hole is not affected by the perturbation. The metric perturbations near the horizon are given. We conclude that given a perturbing test fluid distribution, one can always find a corresponding metric perturbation such that the mass and angular momentum of the black hole are not changed. It was also noticed that when a M, those perturbed spin coefficients and components of the Weyl tensor which determine the intrinsic properties of the incoming null cone near the horizon grow indefinitely.Supported in part by the National Science Foundation under grant No. GP-36687X.On leave from the Institute of Theoretical Physics, University of Warsaw, Warsaw, Poland.     

Emission of massive particles from a rotating black hole

Spectral characteristics were obtained and analyzed for Hawking emission of massive spinless and Dirac particles from a Kerr mini black hole in the limit of long waves (M相似文献   

Gravitational lensing of a star by a rotating black hole

The gravitational lensing of a finite star moving around a rotating Kerr black hole has been numerically simulated. Calculations for the direct image of the star and for the first and second light echoes have been performed for the star moving with an orbital period of 3.22 h around the supermassive black hole SgrA* at the center of the Galaxy. The time dependences for the observed position of the star on the celestial sphere, radiation flux from the star, frequency of detected radiation, and major and minor semiaxes of the lensed image of the star have been calculated and plotted. The detailed observation of such lensing requires a space interferometer such as the Russian Millimetron project.     

Supersymmetry of the extreme rotating toroidal black hole

We study the supersymmetry of the charged rotating toroidal black hole solutions found by Lemos and Zanchin, and show that the only configurations that are supersymmetric are: (i) the non-rotating electrically charged naked singularities already studied by Caldarelli and Klemm, and (ii) an extreme rotating toroidal black hole with zero magnetic and electric charges. For this latter case, the extreme uncharged black hole, we calculate the Killing spinors and show that the configuration preserves the same supersymmetries as the background spacetime.     

Noncommutative geometry-inspired rotating black hole in three dimensions

We find a new rotating black hole in three-dimensional anti-de Sitter space using an anisotropic perfect fluid inspired by the noncommutative black hole. We deduce the thermodynamical quantities of this black hole and compare them with those of a rotating BTZ solution and give corrections to the area law to get the exact nature of the Bekenstein-Hawking entropy.     

Classical non-Abelian particle in the field of a rotating colored black hole

The Hamilton-Jacobi method is used to derive and investigate the equations of motion of a classical non-Abelian particle in the field of a rotating colored black hole.Astrophysical Institute, Kazakh Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 3–7, May, 1993.     

On negative-phase-velocity propagation in the ergosphere of a charged rotating black hole

After adopting a noncovariant approach, we found that the propensity of a rotating black hole to support the propagation of electromagnetic plane waves with negative-phase-velocity (NPV) in its ergosphere is highly sensitive to the presence of charge. The change in shape and size of the ergosphere induced by increasing the black hole's charge gives rise to increased possibilities for NPV propagation. At a fixed ergosphere surface, increasing the black hole's charge concentrates the NPV-supporting regions towards the ergosphere's equator.