We study the dynamics of (i) neutral test particles, (ii) magnetically charged test particles, and (iii) test magnetic dipole around a regular Bardeen black hole surrounded by perfect fluid dark matter (PFDM). It has been shown how the magnetic charge of the black hole and the parameter of the surrounding PFDM can influence the innermost stable circular orbit (ISCO) radius of a test particle. We have found that the ISCO radius is strongly affected as a consequence of the combined effect of the magnetic charge parameter and the perfect fluid dark matter. The black hole magnetic charge parameter $g$ and the combined effect of perfect fluid dark matter can mimic the black hole rotation parameter up to $a/M\approx 0.9$. It has been observed that the ISCO for magnetic dipole disappears at the values exceeding the calculated upper value for the magnetic interaction parameter $β$. The upper limit decreases with the increase of both the dark matter and magnetic charge parameters. Finally, as an astrophysical application, we have analyzed degeneracy effects of spin of Kerr black holes and magnetic charge of regular Bardeen black holes for the different values of the dark matter parameter providing exactly the same value for ISCO radius of a magnetic dipole with the same value of the parameter $β=10.2$ of the magnetar called PSR J1745-2900 orbiting around supermassive black hole Sagittarius A*.
We study the motion of a ring string in the background of the Bardeen-AdS black hole surrounded by the quintessence dark energy. The effects of the magnetic monopole charge, the quintessence state parameter, and the quintessence normalization parameter on the dynamical behavior of the ring string are respectively analyzed. Our numerical results show that the chaotic behavior of string generally becomes stronger with the increase of the quintessence normalization parameter. In particular, the conditions for the existence of chaos are distinctly diverse for two different quintessence state param…
We derive an exact solution of the spherically symmetric Bardeen black hole surrounded by perfect fluid dark matter (PFDM). By treating the magnetic charge $g$ and dark matter parameter $α$ as thermodynamic variables, we find that the thermodynamic first law and the corresponding Smarr formula are satisfied. The thermodynamic stability of the black hole is also studied. The result show that, there exists a critical radius $r_{+}^{C}$, where the heat capacity diverges, suggesting that the black hole is thermodynamically stable in the range $0<r_{+}<r_{+}^{C}$. In addition, the critical radius $…
In the present paper, we investigate the required anisotropy of an exact regular Bardeen black hole characterized by its mass $M$, the nonlinear parameter $g$, the quintessence field parameter $a$ in anti-de sitter spacetime with a static quintessence matter field. We also show that the relative pressure anisotropy, equation of state and the pressure depends on radial coordinate, reflecting the required anisotropy for Bardeen black hole in the quintessence background. Next, we analyze the Joule-Thompson ($JT$) expansion of the black hole spacetime. Treating the cosmological constant as thermod…
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…
The absorption section of black holes surrounded by scalar fields is studied with the sinc approximation in the eikonal limit. The effects of the scalar field on the nonlinear Euler-Heisenberg, the magnetic Bardeen and Reissner-Nordstrom BHs are studied in order to obtain information about how the scalar field affects different BHs.
Thermodynamics, thermodynamic geometry, and the shadow of a Bardeen black hole surrounded by a Kiselev fluid: the role of regularity, asymptotics, and observational self-consistency
In this paper, by exploring the photon motion in the region near the Bardeen black hole, the shadow and observation properties of the black hole surrounded by various accretion models are studied. We analyzed the changes in shadow imaging and observation luminosity when the relevant physical parameters are changed. For the different spherical accretions background, one can find that the radius of shadow and the position of photon sphere do not change, but the observation intensity of shadow in the infalling accretion model is significantly lower than that of the static case. When the black hol…
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 work, we obtain uncharged\charged Kiselev-like black holes as a new class of black hole solutions surrounded by perfect fluid in the context of Rastall theory. Then, we study the specific cases of the uncharged\charged black holes surrounded by regular matter like dust and radiation, or exotic matter like quintessence, cosmological constant and phantom fields. By comparing the Kiselev-like black hole solutions in Rastall theory with the Kiselev black hole solutions in GR, we find an effective perfect fluid behaviour for the black hole's surrounding field. It is shown that the correspon…
Bardeen proposed a gravitationally collapsing magnetic monopole black hole solution which is free of singularity. In this article, we have studied the size and shape of the rotating Bardeen blackhole shadow in presence of perfect fluid dark matter. we have discussed how the parameters such a spin, magnetic monopole charge and influence of dark matter affects the shadow of our blackhole. The apparent shape of the blackhole was studied by using two observables, the radius Rs and the distortion parameter R_s. Further the blackhole emission rate is also studied, we found out that for rotating Bard…
We study some properties of the extended phase space of a quantum-corrected Schwarzschild black hole surrounded by a perfect fluid. In particular we demonstrate that, due to the quantum correction, there exist first and second order phase transitions for a certain range of the state parameter of the perfect fluid, and we explicitly analyze some cases. Besides that, we describe the efficiency of this system as a heat engine and the effect of quantum corrections for different surrounding fluids.
In this work we analyze a solution that mimics the Bardeen solution with a cosmological constant surrounded by quintessence. We show that this solution can be obtained by Einstein equations coupled with nonlinear electrodynamics. We also show that the solution is not always regular and what the conditions for regularity are. We analyze the thermodynamics associated with this type of solution by establishing the form of the Smarr formula and the first law of thermodynamics. We obtain some thermodynamic quantities such as pressure, temperature, heat capacity and isothermal compressibility. Once …
Black Holes Surrounded by Perfect Fluid Dark Matter in Eddington-inspired Born-Infeld Gravity
Instituto Federal de Educação Ciência e Tecnologia do Maranhão（马拉尼昂联邦教育、科学和技术学院）；Universidade Federal do Espírito Santo（圣埃斯皮里图联邦大学）；Universidade Estadual do Maranhão（马拉尼昂州立大学）；Universidade Federal do Pará（帕拉联邦大学）
Basing on the ideas used by Kiselev, we study three black holes surrounded by quintessence and the effects of quintessence on the classical and semiclassical scattering cross-sections. In contrast, the absorption section is studied with the sinc approximation in the eikonal limit. For Schwarzschild, Reissner-Nordström and Bardeen black holes surrounded by quintessence, the values critical of charges and the normalization factor are obtained. We also described the horizons and the extremal condition of the black holes surrounded by quintessence. By setting for the quintessence state parameter i…
In this paper we revisit and extend the prior work of Filho and Bezerra [Phys. Rev D, 64, 084009 (2001)] to rotating dyonic global monopoles in presence of a perfect fluid. We then show that the surface topology at the event horizon, related to the metric computed, is a 2- sphere using the Gauss-Bonnet theorem. By choosing $ω=-1/3, 0, 1/3$ we investigate the effect of dark matter, dust, radiation on the silhouette of black hole. The presence of the global monopole parameter $γ$ and the perfect fluid parameters $\upsilon$, also deforms the shape of black hole's shadow, which has been depicted t…
The Rastall gravity is the modified Einstein general relativity, in which the energy-momentum conservation law is generalized to $T^{μν}_{~~;μ}=λR^{,ν}$. In this work, we derive the Kerr-Newman-AdS (KN-AdS) black hole solutions surrounded by the perfect fluid matter in the Rastall gravity using the Newman-Janis method and Mathematica package. We then discuss the black hole properties surrounded by two kinds of specific perfect fluid matter, the dark energy ($ω=-2/3$) and the perfect fluid dark matter ($ω=-1/3$). Firstly, the Rastall parameter $κλ$ could be constrained by the weak energy condit…
In this work, we consider a rotating charged black hole surrounded by perfect fluid dark matter. We consider the system to be immersed in non-magnetised, pressureless plasma. First, we evaluate the null geodesics in order to study the co-rotating and counter rotating photon orbits. Further, we analyse the null geodesics to calculate the celestial coordinates ($α, β$). The celestial coordinates are used to determine the black hole shadow radius ($R_s$). Thereafter, we observe and analyse the effects of black hole spacetime, perfect fluid dark matter and plasma parameters ($a$, $Q$, $χ$, $k$) on…
We present the generalization of a regular black hole surrounded by quintessence, considering Bardeen-like solutions added with this fluid. We also compare our solution particularized to the Bardeen one with those found in the recent literature, showing that some of them are inconsistent since they add quintessence "by hand", neglecting also the interesting behavior of the complete solution nearby the origin. Then, we present the correct way to implement the quintessential fluid in more general four-dimensional regular black hole geometries and explore some of its consequences, such as removin…
The first law of black hole mechanics (in the form derived by Wald), is expressed in terms of integrals over surfaces, at the horizon and spatial infinity, of a stationary, axisymmetric black hole, in a diffeomorphism invariant Lagrangian theory of gravity. The original statement of the first law given by Bardeen, Carter and Hawking for an Einstein-perfect fluid system contained, in addition, volume integrals of the fluid fields, over a spacelike slice stretching between these two surfaces. When applied to the Einstein-perfect fluid system, however, Wald's methods yield restricted results. The…
In this paper, we investigate the geodesic motion of massive and massless test particles in the vicinity of a black hole space-time surrounded by perfect fluid (quintessence, dust, radiation, cosmological constant and phantom) in Rastall theory. We obtain the full set of analytical solutions of the geodesic equation of motion in the space-time of this black hole. For all cases of perfect fluid, we consider some different values of Rastall coupling constant $kλ$ so that the equations of motion have integer powers of $\tilde{r}$ and also can be solved analytically. These analytical solutions are…
We analysed the shadow cast by charged rotating black hole (BH) in presence of perfect fluid dark matter (PFDM). We studied the null geodesic equations and obtained the shadow of the charged rotating BH to see the effects of PFDM parameter $γ$, charge $Q$ and rotation parameter $a$, and it is noticed that the size as well as the shape of BH shadow is affected due to PFDM parameter, charge and rotation parameter. Thus, it is seen that the presence of dark matter around a BH affects its spacetime. We also investigated the influence of all the parameters (PFDM parameter $γ$, BHs charge $Q$ and ro…
Thermal chaos under spatially/temporally periodic perturbations in the extended phase space of Bardeen-AdS black holes surrounded by quintessence dark energy is investigated. The occurring condition of chaos is obtained with the Melnikov integral. It is shown that spatial chaos is always supposed to occur even for a tiny spatially periodic perturbation imposed on the equilibrium configuration. However, the temporal chaos will arise in the unstable spinodal region only if the given perturbed amplitude γ is larger than a critical value γc. The value of γc is determined by the magnetic monopole c…
In the string theory, the fundamental blocks of nature are not particles but one-dimensional strings. Therefore, a generalization of this idea is to think of it as a cloud of strings. Rodrigues et al. embedded the black bounces spacetime into the string cloud, which demonstrates that the existence of the string cloud makes the Bardeen black hole singular, while the black bounces spacetime remains regular. On the other hand, the echoes are the correction to the late stage of the quasinormal ringing for a black hole, which is caused by the deviation of the spacetime relative to the initial black…
Periodic Orbits and Their Gravitational-Wave Signatures around a Rotating Black Hole Surrounded by Perfect Fluid Dark Matter
Zhejiang University of Technology（浙江工业大学）；United Center for Gravitational Wave Physics (UCGWP), Zhejiang University of Technology（引力波物理联合中心（UCGWP），浙江工业大学）；Bahauddin Zakariya University, Vehari Campus（巴哈丁·扎卡里亚大学，韦哈里校区）；Khazar University（哈扎尔大学）
Quantum Oppenheimer-Snyder Black Holes with a Cloud of Strings Surrounded by Perfect Fluid Dark Matter
The Assam Royal Global University（阿萨姆皇家全球大学）；Secretaria da Educação do Ceará (SEDUC), Coordenadoria Regional de Desenvolvimento da Educação (CREDE 9)（塞阿拉州教育厅（SEDUC），区域教育发展协调局（CREDE 9））；Echahid Cheikh Larbi Tebessi University（谢赫·拉里比·特贝西烈士大学）；Khazar University（哈扎尔大学）
In this paper, we study thermodynamics and thermodynamic geometry of a black hole surrounded by the perfect fluid in Rastall theory. In particular, we calculate the physical quantity like mass, temperature and heat capacity of the system for two different cases. From the resulting heat capacity, we emphasize stability of the system. Following Weinhold, Ruppiner, Quevedo and HPEM formalism, thermodynamic geometry of this black hole in Rastall gravity is also analyzed. We find that the singular points of the curvature scalar of Ruppeiner and HPEM metrics entirely coincides with zero points of th…
Probing Bardeen-Kiselev black hole with cosmological constant caused by Einstein equations coupled with nonlinear electrodynamics using quasinormal modes and greybody bounds
Equatorial periodic orbits and gravitational wave signatures in Euler-Heisenberg black holes surrounded by perfect fluid dark matter
Madhabdev University（马哈德夫大学）；Khazar University（阿塞拜疆哈萨尔大学）；Pacif Institute of Cosmology and Selfology (PICS)（太平洋宇宙学与自我学研究所（PICS））；Eastern Mediterranean University（东地中海大学）
In this paper we investigate circular orbits for test particles around Schwarzschild-de Sitter (dS) black hole surrounded by perfect fluid dark matter. We determine the region of circular orbits bounded by innermost and outermost stable circular orbits. We show that the impact of the perfect fluid dark matter shrinks the region where circular orbits can exist as the values of both innermost and outermost stable circular orbits decrease. We find that for specific lower and upper values of dark matter parameter there exist double matching values for inner and outermost stable circular orbits. It…
In this paper, we test the weak cosmic censorship conjecture (WCCC) for the Reissner-Nordström-de Sitter (RN-dS) black hole surrounded by perfect fluid dark matter. We consider a spherically symmetric perturbation on deriving linear and non-linear order perturbation inequalities by applying new version of gedanken experiments well accepted from the work of Sorce and Wald. Contrary to the well-known result that the Reissner-Nordström (RN) black hole could be overcharged under linear order particle accretion it is hereby shown that the same black hole in perfect fluid dark matter with cosmologic…
