论文标题
爱因斯坦四分之一重力：阴影，信号和稳定性
Einstein Quartic Gravity: Shadows, Signals, and Stability
论文作者
论文摘要
使用持续的分数ANSATZ，我们获得了Einsteinian四分之一重力（EQG）的球形对称黑洞溶液的分析近似，在爱因斯坦立方体重力（ECG）之后，下一个最简单的准广泛性重力（GQTG）。该近似解决方案在地平线以外的任何地方都是有效的，我们使用它来研究黑洞附近大规模测试机构的轨道，专门计算最内向的稳定圆形轨道。使用Shapiro Time延迟，我们计算EQG耦合参数上的约束。最后，我们计算一个EQG黑洞的阴影，并确定它比其在质量相同值的总体相对论中比其爱因斯坦的同行大。通过将我们的结果应用于银河系中心的射手座A*（sgr a*），我们发现，类似于ECG黑洞，偏离了一般相对性的情况很小，但对于EQG黑洞来说是可区分的。
Using a continued fraction ansatz we obtain an analytic approximation for a spherically symmetric black hole solution to Einsteinian Quartic Gravity (EQG), the next simplest Generalized Quasi-Topological Gravity (GQTG) after Einsteinian Cubic Gravity (ECG). This approximate solution is valid everywhere outside of the horizon and we use it to investigate the orbit of massive test bodies near a black hole, specifically computing the innermost stable circular orbit. Using Shapiro time delay we calculate the constraints on the EQG coupling parameter. Finally we compute the shadow of an EQG black hole and figure out it to be larger than its Einsteinian counterpart in general relativity for the same value of the mass. By applying our results to Sagittarius A* (Sgr A*) at the center of Milky Way we find, similar to ECG black holes, that departures from general relativity are small but distinguishable for EQG black holes.
