Weak deflection angle of a dirty black hole

Pantig, Reggie C.; Rodulfo, Emmanuel T.

doi:10.1016/j.cjph.2020.06.015

Cited by 56 publications

(31 citation statements)

References 64 publications

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“…Theoretical analysis of shapes of the black hole shadows have been recently considered in a great number of papers (see, for example, [76][77][78][79][80][81][82][83] and references therein). The radius of the photon sphere r ph of a spherically symmetric black hole is determined by means of the following function: (see, for example, [84,85] and references therein)…”

Section: Radius Of the Black-hole Shadowmentioning

confidence: 99%

Quasinormal modes, stability and shadows of a black hole in the 4D Einstein–Gauss–Bonnet gravity

2020

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Recently a D-dimensional regularization approach leading to the non-trivial $$(3+1)$$ ( 3 + 1 ) -dimensional Einstein–Gauss–Bonnet (EGB) effective description of gravity was formulated which was claimed to bypass the Lovelock’s theorem and avoid Ostrogradsky instability. Later it was shown that the regularization is possible only for some broad, but limited, class of metrics and Aoki et al. (arXiv:2005.03859) formulated a well-defined four-dimensional EGB theory, which breaks the Lorentz invariance in a theoretically consistent and observationally viable way. The black-hole solution of the first naive approach proved out to be also the exact solution of the well-defined theory. Here we calculate quasinormal modes of scalar, electromagnetic and gravitational perturbations and find the radius of shadow for spherically symmetric and asymptotically flat black holes with Gauss–Bonnet corrections. We show that the black hole is gravitationally stable when ($$-16 M^2<\alpha \lessapprox 0.6 M^2$$ - 16 M 2 < α ⪅ 0.6 M 2 ). The instability in the outer range is the eikonal one and it develops at high multipole numbers. The radius of the shadow $$R_{Sh}$$ R Sh obeys the linear law with a remarkable accuracy.

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Section: Radius Of the Black-hole Shadowmentioning

confidence: 99%

Quasinormal modes, stability and shadows of a black hole in the 4D Einstein–Gauss–Bonnet gravity

2020

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“…Previously, the shadow images of metric (3) and rotating counterpart of metric (3) have been studied in Refs. [62][63][64][65].…”

Section: Model Imentioning

confidence: 99%

“…: V,-vol particle plays a key role in many astrophysical processes, yet is one of the greatest unsolved mysteries. In recent papers, the effect of dark matter on black hole shadow has been investigated [62][63][64][65][66]. In this paper, we aim to study the possibility of identifying dark matter in the galactic center based on the physical properties of the electromagnetic radiation emitted from a optical-thin disk region around the static and spherically symmetric black hole.…”

Section: Introductionmentioning

confidence: 99%

Imprints of dark matter on black hole shadows using spherical accretions

2021

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We study the possibility of identifying dark matter in the galactic center from the physical properties of the electromagnetic radiation emitted from an optically-thin disk region around a static and spherically symmetric black hole. In particular, we consider two specific models for the optical-thin disk region: a gas at rest and a gas in a radial free fall. Due to the effect of dark matter on the spacetime geometry, we find that the dark matter can increase or decrease the intensity of the electromagnetic flux radiation depending on the dark matter model. To this end, we analyze two simple dark matter models having different mass functions $${\mathcal {M}}(r)$$ M ( r ) , with a matter mass M, thickness $$\Delta r_s$$ Δ r s along with a dark matter core radius surrounding the black hole. In addition to that, we explore the scenario of a perfect fluid dark matter surrounding the black hole. We show that in order to have significant effect of dark matter on the intensity of the electromagnetic flux radiation, a high energy density of dark matter near the black hole is needed. We also find that the surrounding dark matter distribution plays a key role on the shadow radius and the intensity of the electromagnetic flux radiation, respectively. Finally we have used the relation between the shadow radius and the quasinormal modes (QNMs) to compute the real part of QNM frequencies.

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“…The weak deflection angle, using the GBT for various spacetimes, was studied by many physicists. For example, the deflection angle of light was studied for BHs and wormholes by the following authors [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53]: Ovgun et al studied for different spacetimes, such as Schwarzschild-like spacetime, the bumblebee gravity model [54][55][56][57][58][59][60], and Javed et al studied the impact of various matter fields [61][62][63][64][65]. Next, Ishihara et al [66] showed that it is conceivable to calculate the weak deflection angle using the finite-distances method.…”

Section: Kdsmentioning

confidence: 99%

Weak Deflection Angle and Shadow by Tidal Charged Black Hole

2021

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In this article, we calculate the deflection angle of a tidal charged black hole (TCBH) in weak field limits. First, we obtain the Gaussian optical curvature and then apply the Gauss–Bonnet theorem on it. With the help of Gibbons–Werner method, we are able to calculate the light’s deflection angle by TCBH in weak field limits. After calculating the deflection angle of light, we check the graphical behavior of TCBH. Moreover, we further find the light’s deflection angle in the presence of the plasma medium and also check the graphical behavior in the presence of the plasma medium. Moreover, we investigate the shadow of TCBH. For calculating the shadow, we first find the null geodesics around the TCBH and then find its shadow radius. We also obtain TCBH’s shadow in the plasma medium. Hence, we discuss the shadow of the TCBH, using the M87* parameters announced by the event horizon telescope.

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Weak deflection angle of a dirty black hole

Cited by 56 publications

References 64 publications

Quasinormal modes, stability and shadows of a black hole in the 4D Einstein–Gauss–Bonnet gravity

Quasinormal modes, stability and shadows of a black hole in the 4D Einstein–Gauss–Bonnet gravity

Imprints of dark matter on black hole shadows using spherical accretions

Weak Deflection Angle and Shadow by Tidal Charged Black Hole

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