论文标题

重力镜头由带电的黑洞正规化$ 4D $ EINSTEIN-GAUSS BONNET重力

Gravitational lensing by charged black hole in regularized $4D$ Einstein-Gauss-Bonnet gravity

论文作者

Kumar, Rahul, Islam, Shafqat Ul, Ghosh, Sushant G.

论文摘要

在较高的曲率重力中,最广泛研究的理论是所谓的爱因斯坦 - 加斯 - 尼斯(EGB)重力,其Lagrangian包含Einstein术语,具有二次曲率术语的GB组合,GB期限的GB术语和GB项的组合产生了$ D \ d \ egeq5 $ d \ geq5 $ d \ defial dynamics。最近,正规化,$ d \至4 $的限制,EGB重力以及由此产生的正规化$ 4D $ EGB重力有效期为$ 4D $。我们认为,在$ 4D $ EGB重力理论中充电的黑洞通过重力镜头来计算强场上的光偏转系数$ \ bar {a} $和$ \ bar {b} $,而前者则随着GB参数$α$和电荷$ Q $的增加而增加。我们还发现偏转角$α_d$的下降,角位置$θ_ {\ infty} $减小较慢,并且对光子轨道$ u_ {m {m {m {m} $的影响参数较快,但是角度分离$ s $会随着$α$和收费$ q $而更快地增加。我们将我们的结果与一般相对论中的类似黑洞的结果进行了比较,并且在超级质量黑洞SGR A*和M87*的情况下,还应用了形式主义来讨论天体物理的后果。

Among 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\geq5$. Recently there has been a surge of interest in regularizing, a $ D \to 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 $\bar{a}$ and $\bar{b}$, while the former increases with increasing GB parameter $α$ and charge $q$, later decrease. We also find a decrease in the deflection angle $α_D$, angular position $θ_{\infty}$ decreases more slowly and impact parameter for photon orbits $u_{m}$ more quickly, but angular separation $s$ increases more rapidly with $α$ 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*.

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