论文标题
无效测量学的高自旋扩展
High spin expansion for null geodesics
论文作者
论文摘要
我们考虑了Kerr时空中无效的测量学的高自旋膨胀。我们将无效的大地测量方程依次扩展到偏离肢体的较高阶段。通过匹配的渐近扩展方法，可以通过分析获得径向积分。事实证明，分析表达式对移动的卡特常数$ q $的价值非常敏感。我们表明，对于$ Q $，分析表达式可用于研究天体物理黑洞（如M87*）的观察性电磁特征。但是，对于小$ Q $，高自旋扩展方法只能应用于（近）极端黑洞。
We consider the high spin expansion for the null geodesics in the Kerr spacetime. We expand the null geodesic equation successively to higher orders in deviation from extremity. Via the method of matched asymptotic expansion, the radial integrals are obtained analytically. It turns out that the analytic expressions are very sensitive to the value of the shifted Carter constant $q$. We show that for a large $q$, the analytic expressions can be used to study observational electromagnetic signatures for astrophysical black holes like M87*. However, for a small $q$, the high spin expansion method can only be applied to (near-) extreme black holes.
