scholarly journals Weak deflection angle by electrically and magnetically charged black holes from nonlinear electrodynamics

2021 ◽  
Vol 104 (2) ◽  
Author(s):  
Qi-Ming Fu ◽  
Li Zhao ◽  
Yu-Xiao Liu
Universe ◽  
2019 ◽  
Vol 5 (10) ◽  
pp. 205 ◽  
Author(s):  
Irina Dymnikova ◽  
Evgeny Galaktionov

We study the dynamics of electromagnetic fields of regular rotating electrically charged black holes and solitons replacing naked singularities in nonlinear electrodynamics minimally coupled to gravity (NED-GR). They are related by electromagnetic and gravitational interactions and described by the axially symmetric NED-GR solutions asymptotically Kerr-Newman for a distant observer. Geometry is described by the metrics of the Kerr-Schild class specified by T t t = T r r ( p r = − ρ ) in the co-rotating frame. All regular axially symmetric solutions obtained from spherical solutions with the Newman-Janis algorithm belong to this class. The basic generic feature of all regular objects of this class, both electrically charged and electrically neutral, is the existence of two kinds of de Sitter vacuum interiors. We analyze the regular solutions to dynamical equations for electromagnetic fields and show which kind of a regular interior is favored by electromagnetic dynamics for NED-GR objects.


2020 ◽  
Vol 35 (23) ◽  
pp. 2050136
Author(s):  
Nilofar Rahman ◽  
Masum Murshid ◽  
Farook Rahaman ◽  
Mehedi Kalam

We construct a thin-shell wormhole using the cut and paste technique from regular charged black holes with a nonlinear electrodynamics source (proposed by Balart and Vagenas). Using Darmois–Israel formalism we determine the surface stresses, which are localized at the wormhole throat. We also determine the amount of exotic matter present in the shell. To analyze the stability of the constructed wormhole we consider an equation of state as a linear perturbation. The stability region is shown in the graph by varying the values of the parameter.


Author(s):  
Sergey Il'ich Kruglov

The logarithmic correction to Bekenshtein-Hawking entropy in the framework of 4D Einstein$-$Gauss$-$Bonnet gravity coupled with nonlinear electrodynamics is obtained. We explore the black hole solution with the spherically symmetric metric. The logarithmic term in the entropy has a structure similar to the entropy correction in the semi-classical Einstein equations which mimics the quantum correction to the area low. The energy emission rate of black holes and energy conditions are studied. Quasinormal modes of black holes are investigated. The gravitational lensing of light around BHs was investigated. We calculated the deflection angle for some model parameters.


2021 ◽  
Vol 2021 (04) ◽  
pp. 008
Author(s):  
Khadije Jafarzade ◽  
Mahdi Kord Zangeneh ◽  
Francisco S.N. Lobo

2007 ◽  
Vol 22 (17) ◽  
pp. 1217-1231 ◽  
Author(s):  
IVAN ZH. STEFANOV ◽  
STOYTCHO S. YAZADJIEV ◽  
MICHAIL D. TODOROV

The no-scalar-hair conjecture rules out the existence of asymptotically flat black holes with a scalar dressing for a large class of theories. No-scalar-hair theorems have been proved for the cases of neutral black holes and for charged black holes in the Maxwell electrodynamics. These theorems, however, do not apply in the case of nonlinear electrodynamics. In the present work numerical solutions describing charged black holes coupled to Euler–Heisenberg type nonlinear electrodynamics in scalar–tensor theories of gravity with massless scalar field are found. In comparison to the corresponding solution in General Relativity the presented solution has a simpler causal structure the reason for which is the presence of the scalar field. The present class of black holes has a single, nondegenerate horizon, i.e. its causal structure resembles that of the Schwarzschild black hole.


2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Rahul Kumar ◽  
Shafqat Ul Islam ◽  
Sushant G. Ghosh

AbstractAmong the higher curvature gravities, the most extensively studied theory is the so-called Einstein–Gauss–Bonnet (EGB) gravity, whose Lagrangian contains Einstein term with the GB combination of quadratic curvature terms, and the GB term yields nontrivial gravitational dynamics in $$ D\ge 5$$ D ≥ 5 . Recently there has been a surge of interest in regularizing, a $$ D \rightarrow 4 $$ D → 4 limit of, the EGB gravity, and the resulting regularized 4D EGB gravity valid in 4D. We consider gravitational lensing by Charged black holes in the 4D EGB gravity theory to calculate the light deflection coefficients in strong-field limits $$\bar{a}$$ a ¯ and $$\bar{b}$$ b ¯ , while former increases with increasing GB parameter $$\alpha $$ α and charge q, later decrease. We also find a decrease in the deflection angle $$\alpha _D$$ α D , angular position $$\theta _{\infty }$$ θ ∞ decreases more slowly and impact parameter for photon orbits $$u_{m}$$ u m more quickly, but angular separation s increases more rapidly with $$\alpha $$ α and charge q. We compare our results with those for analogous black holes in General Relativity (GR) and also the formalism is applied to discuss the astrophysical consequences in the case of the supermassive black holes Sgr A* and M87*.


2017 ◽  
Vol 32 (39) ◽  
pp. 1750219 ◽  
Author(s):  
Leonardo Balart ◽  
Sharmanthie Fernando

It is well known that the Smarr formula does not hold for black holes in nonlinear electrodynamics. The main reason for this is the fact that the trace of the energy–momentum tensor for nonlinear electrodynamics does not vanish as it is for Maxwell’s electrodynamics. Starting from the Komar integral, we derived a new Smarr-type formula for spherically symmetric static electrically charged black hole solutions in nonlinear electrodynamics. We show that this general formula is in agreement with some that are obtained for black hole solutions with nonlinear electrodynamics.


2009 ◽  
Vol 80 (10) ◽  
Author(s):  
Hernán A. González ◽  
Mokhtar Hassaïne ◽  
Cristián Martínez

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