论文标题
X射线电晕折射率对AGN发射线的影响
Effects of the refractive index of the X-ray corona on the emission lines in AGN
论文作者
论文摘要
X射线反射来自积聚光盘会产生特征发射线，使我们能够探测AGN中最内部的区域。我们在Riemannian几何光学框架下研究了这些发射线，其中电晕的折射率为$ n \ neq 1 $。外面的空白空间是$ n = 1 $的真空吸尘器。修改了Kerr度量，以追踪由于黑洞的重力，而且还依赖于$ n $的冠状血浆而弯曲的光线。 $ n $的选择改变了无效的测量学，从而产生类似于光偏转的效果。对于带有$ n> 1 $的电晕，电晕内远侧的光盘覆盖了观察者的天空上的一个较大区域，增强了线的蓝色翅膀，并在蓝色峰和延伸的红色尾巴之间产生更大的通量差异。当$ n <1 $时，可以看到反效应。此外，具有$ n> 1 $和$ n <1 $的电晕可能会导致蓝机翼（$ΔG_{max} $）的额外变化，分别向更高和更低的能量。当倾斜角度为$ \ gtrsim 60^\ circ $并且电晕延伸至$ \ gtrsim 5r_g $时，这些效果更加突出。为了获得$ΔG_ {\ rm max} \ gtrsim 0.01 $的线移的偏差，Corona的折射率和空白空间的折射率之间的差异必须为$Δn\ gtrsim 0.5％$。最后，镜头电晕可能会影响光子的到达时间，这可能会影响这些发射线的可变性
X-ray reflection from an accretion disc produces characteristic emission lines allowing us to probe the innermost regions in AGN. We investigate these emission lines under a framework of Riemannian geometrical optics where the corona has a refractive index of $n \neq 1$. The empty space outside is a vacuum with $n = 1$. The Kerr metric is modified to trace the light rays that are bent due to not only the gravity of the black hole, but also the effects of coronal plasma dependent on $n$. The choice of $n$ alters the null geodesics, producing the effect which is analogous to the light deflection. For the corona with $n > 1$, the disc on the far side within the corona covers a larger area on the observer' sky, enhancing the blue wing of the line and producing more flux difference between the blue peak and extended red tail. The inverse effects are seen when $n < 1$. Moreover, the corona with $n > 1$ and $n < 1$ could induce extra shifts in the blue wing ($Δg_{max}$) to higher and lower energy, respectively. These effects are more prominent when the inclination angle is $\gtrsim 60^\circ$ and the corona extends to $\gtrsim 5r_g$. To obtain the deviation of the line shift of $Δg_{\rm max} \gtrsim 0.01$, the difference between the refractive index of the corona and that of the empty space must be $Δn \gtrsim 0.5%$. Finally, the lensing corona can influence the arrival time of photons that may affect the observed variability of these emission lines
