scholarly journals GRAVITATIONAL LENSING IN THE WEAK FIELD LIMIT BY A BRANEWORLD BLACK HOLE

2005 ◽  
Vol 20 (32) ◽  
pp. 2487-2496 ◽  
Author(s):  
A. S. MAJUMDAR ◽  
NUPUR MUKHERJEE
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Lensing ◽  
Cosmic Ray ◽  
Weak Field ◽  
High Energy ◽  
High Energy Particle ◽  
Field Limit ◽  
Weak Field Limit ◽  
Point Light

The existence of braneworld black holes may be of primordial origin, or may even be produced in high energy particle collisions in the laboratory and in cosmic ray showers as well. These black holes obey a modified mass–radius relationship compared to standard Schwarzschild black holes. Using the variational principle we calculate the bending angle of a light ray near the horizon of a braneworld black hole in the weak field limit. We next derive the expressions of several lensing quantities like the Einstein radius and the magnification for a point light source. These expressions are modified compared to the lensing quantities for standard Schwarzschild black holes and contain the scale of the extra dimensions.

scholarly journals ENERGY DISTRIBUTION OF (2+1)-DIMENSIONAL BLACK HOLES WITH NONLINEAR ELECTRODYNAMICS

2009 ◽  
Vol 24 (34) ◽  
pp. 2777-2785 ◽  
Author(s):  
LEONARDO BALART
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Black Hole Solution ◽  
Weak Field ◽  
Nonlinear Electrodynamics ◽  
Field Limit ◽  
Energy Distributions ◽  
Weak Field Limit ◽  
Dimensional Black Hole ◽  
Black Hole Solutions

The energy distributions for a black hole solution resulting from coupling electrodynamics and gravity in (2+1) dimensions are obtained. This solution considers the correction for a (2+1) static charged black hole from the first contribution of the weak field limit of one-loop QED in (2+1) dimensions. The Einstein and Møller energy–momentum prescriptions are used to evaluate the energy distributions associated with the mentioned (2+1)-dimensional black hole and other (2+1) black hole solutions coupled with nonlinear electrodynamics. A relation that connects the coefficients of both prescriptions is established.

scholarly journals Weak Deflection Angle of some Classes of non-linear Electrodynamics Black Holes via Gauss-Bonnet Theorem

2020 ◽  
Author(s):  
Hasan El Moumni ◽  
Karima Masmar ◽  
Ali Övgün
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Lensing ◽  
Deflection Angle ◽  
Weak Field ◽  
Leading Order ◽  
Plasma Medium ◽  
Non Linear ◽  
The Deflection Angle ◽  
Bonnet Theorem

In this paper, we study the gravitational lensing by some black hole classes within the non-linear electrodynamics in weak field limits. First, we calculate an optical geometry of the non-linear electrodynamics black hole then we use the Gauss-Bonnet theorem for finding deflection angle in weak field limits. The effect of non-linear electrodynamics on the deflection angle in leading order terms is studied. Furthermore, we discuss the effects of the plasma medium on the weak deflection angle.

scholarly journals BLACK HOLES IN THEORIES WITH LARGE EXTRA DIMENSIONS: A REVIEW

2004 ◽  
Vol 19 (29) ◽  
pp. 4899-4951 ◽  
Author(s):  
PANAGIOTA KANTI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Radiation ◽  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
Life Time ◽  
High Energy ◽  
High Energy Particle ◽  
Radiation Spectra ◽  
Black Hole Background

We start by reviewing the existing literature on the creation of black holes during high-energy particle collisions, both in the absence and in the presence of extra, compact, spacelike dimensions. Then, we discuss in detail the properties of the produced higher-dimensional black holes, namely the horizon radius, temperature and life-time, as well as the physics that governs the evaporation of these objects, through the emission of Hawking radiation. We first study the emission of visible Hawking radiation on the brane: we derive a master equation for the propagation of fields with arbitrary spin in the induced-on-the-brane black hole background, and we review all existing results in the literature for the emission of scalars, fermions and gauge bosons during the spin-down and Schwarzschild phases of the life of the black hole. Both analytical and numerical results for the graybody factors and radiation spectra are reviewed and exact results for the number and type of fields emitted on the brane as a function of the dimensionality of space–time are discussed. We finally study the emission of Hawking radiation in the bulk: graybody factors and radiation spectra are presented for the emission of scalar modes, and the ratio of the missing energy over the visible one is calculated for different values of the number of extra dimensions.

scholarly journals Effect of Multipole Moments in the Weak Field Limit of a Black Hole Plus Halo Potential

2021 ◽  
Vol 908 (1) ◽  
pp. 74
Author(s):  
Fredy L. Dubeibe ◽  
Tareq Saeed ◽  
Euaggelos E. Zotos
Keyword(s):  
Black Hole ◽  
Weak Field ◽  
Multipole Moments ◽  
Field Limit ◽  
Weak Field Limit

scholarly journals Constraining the spacetime spin using time delay in stationary axisymmetric spacetimes

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Haotian Liu ◽  
Junji Jia
Keyword(s):  
Black Hole ◽  
Time Delay ◽  
Gravitational Lensing ◽  
Angular Position ◽  
Weak Field ◽  
Weak Field Limit ◽  
Perturbative Method ◽  
Total Travel Time ◽  
Sgr A ◽  
The Impact

AbstractTotal travel time t and time delay $$\Delta t$$ Δ t between images of gravitational lensing (GL) in the equatorial plane of stationary axisymmetric (SAS) spacetimes for null and timelike signals with arbitrary velocity are studied. Using a perturbative method in the weak field limit, t in general SAS spacetimes is expressed as a quasi-series of the impact parameter b with coefficients involving the source-lens distance $$r_s$$ r s and lens-detector distances$$r_d$$ r d , signal velocity v, and asymptotic expansion coefficients of the metric functions. The time delay $$\Delta t$$ Δ t to the leading order(s) were shown to be determined by the spacetime mass M, spin angular momentum a and post-Newtonian parameter $$\gamma $$ γ , and kinematic variables $$r_s,~r_d,~v$$ r s , r d , v and source angular position $$\beta $$ β . When $$\beta \ll \sqrt{aM}/r_{s,d}$$ β ≪ aM / r s , d , $$\Delta t$$ Δ t is dominated by the contribution linear to spin a. Modeling the Sgr A* supermassive black hole as a Kerr–Newman black hole, we show that as long as $$\beta \lesssim 1.5\times 10^{-5}$$ β ≲ 1.5 × 10 - 5 [$$^{\prime \prime }$$ ″ ], then $$\Delta t$$ Δ t will be able to reach the $$\mathcal {O}(1)$$ O ( 1 ) second level, which is well within the time resolution of current GRB, gravitational wave and neutrino observatories. Therefore measuring $$\Delta t$$ Δ t in GL of these signals will allow us to constrain the spin of the Sgr A*.

BRANEWORLD BLACK HOLES IN COSMOLOGY AND ASTROPHYSICS

2005 ◽  
Vol 14 (07) ◽  
pp. 1095-1129 ◽  
Author(s):  
A. S. MAJUMDAR ◽  
N. MUKHERJEE
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Lensing ◽  
Strong Field ◽  
Planck Scale ◽  
High Energy ◽  
Field Equations ◽  
Large Extra Dimension ◽  
Gravitational Field Equations ◽  
Fundamental Scale

The braneworld description of our universe entails a large extra dimension and a fundamental scale of gravity that might be lower by several orders of magnitude compared to the Planck scale. An interesting consequence of the braneworld scenario is in the nature of spherically symmetric vacuum solutions to the brane gravitational field equations which could represent black holes with properties quite distinct compared to ordinary black holes in 4-dimensions. We discuss certain key features of some braneworld black hole geometries. Such black holes are likely to have diverse cosmological and astrophysical ramifications. The cosmological evolution of primordial braneworld black holes is described highlighting their longevity due to modified evaporation and effective accretion of radiation during the early braneworld high energy era. Observational abundance of various evaporation products of the black holes at different eras impose constraints on their initial mass fraction. Surviving primordial black holes could be candidates of dark matter present in galactic haloes. We discuss gravitational lensing by braneworld black holes. Observables related to the relativistic images of strong field gravitational lensing could in principle be used to distinguish between different braneworld black hole metrics in future observations.

scholarly journals ENERGY DISTRIBUTION IN THE DYADOSPHERE OF A REISSNER–NORDSTRÖM BLACK HOLE IN MØLLER'S PRESCRIPTION

2006 ◽  
Vol 21 (25) ◽  
pp. 1947-1956 ◽  
Author(s):  
ELIAS C. VAGENAS
Keyword(s):  
Black Hole ◽  
Energy Distribution ◽  
Weak Field ◽  
Specific Form ◽  
Vacuum Fluctuations ◽  
Field Limit ◽  
Weak Field Limit ◽  
Momentum Distributions ◽  
Energy And Momentum ◽  
Momentum Complex

The energy and momentum distributions in the dyadosphere of a Reissner–Nordström black hole are evaluated. The Møller's energy-momentum complex is employed for this computation. The spacetime under study is modified due to the effects of vacuum fluctuations in the dyadosphere. Therefore, the corrected Reissner–Nordström black hole metric takes into account the first contribution of the weak field limit of one-loop QED. Furthermore, a comparison and a consequent connection between our results and those already existing in the literature is provided. We hypothesize that when the energy distribution is of specific form there is a relation that connects the coefficients in the Einstein's prescription with those in the Møller's prescription.

Gravitational lensing by multi-polytropic wormholes

2020 ◽  
Vol 98 (11) ◽  
pp. 1046-1054
Author(s):  
S.N. Sajadi ◽  
N. Riazi
Keyword(s):  
Gravitational Lensing ◽  
Deflection Angle ◽  
Weak Field ◽  
Light Curves ◽  
Energy Conditions ◽  
Field Limit ◽  
Asymptotically Flat ◽  
Weak Field Limit ◽  
Polytropic Equation ◽  
The Deflection Angle

We obtain static, asymptotically flat, multi-polytropic wormhole solutions in the framework of general relativity. We examine gravitational lensing in the presence of the wormhole and calculate the deflection angle for both weak and strong fields. We investigate microlensing in the weak field limit and obtain corresponding light curves for both galactic and extragalactic situations. We discuss the astrophysical motivation of considering the multi-polytropic equation of state that supports the wormhole geometry. Finally, we investigate the energy conditions.

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