四维Einstein-Gauss-Bonnet引力时空中非线性电磁场对光线偏折的影响

Effect of Nonlinear Electrodynamics on the Deflection of Light in 4D Einstein-Gauss-Bonnet Gravity

文章研究了含非线性电磁场的四维爱因斯坦-高斯-博内引力时空中的弱引力透镜现象。首先应用高斯-博内定理计算了含非线性电磁场的四维爱因斯坦-高斯-博内引力中的确切带电黑洞解得时空中光线的弱偏转角,并讨论了高斯-博内参数和非线性参数对偏转角的影响。此外,还利用类光测地线法计算了该黑洞的阴影半径。利用来自于事件视界望远镜的M87*黑洞观测数据限制了高斯-博内参数和磁荷,并讨论了非线性参数对观测值的影响。

In this paper,we investigate the weak gravitational lensing in the background of 4D Einstein-Gauss-Bonnet coupled with nonlinear electrodynamics.Using Gauss-Bonnet theorem,we first compute the weak deflection angle of light from the exact charged black hole in 4D Einstein-Gauss-Bonnet gravity coupled with nonlinear electrodynamics.Then,we discuss the effects of the Gauss-Bonnet parameter and nonlinear parameter on the weak deflection angle of the black hole.Furthermore,we also calculate the shadow radius of the black hole by applying the null geodesics method.Then,we provide some constraints on the Gauss-Bonnet parameter and charge of the black hole using the observations of M87*from Event Horizon Telescope and discuss the effect of the nonlinear parameter on the observed value.