发表机构
Università di Salerno; Istituto Nazionale di Fisica Nucleare, Sezione di Napoli; ShanghaiTech University（萨莱诺大学; 意大利国家核物理研究所，那不勒斯分部; 上海科技大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究针对缓慢旋转克尔黑洞时空中的致密源，利用强偏转极限推导高阶像干涉信号的解析描述，建立克尔自旋参数与像角位移的关系，为探测黑洞自旋和源动力学提供分析框架。
AI 中文摘要
黑洞不稳定光子区附近轨道光子产生的高阶像编码了时空几何信息，并留下了可通过长干涉基线探测的特征信号。我们针对缓慢旋转克尔黑洞时空中的致密源，建立了这些信号的解析描述。利用强偏转极限，我们在黑洞自旋的线性阶下推导了有限大小源的复可见度函数。对于静态赤道源，我们得到了无量纲克尔自旋参数与属于同一宇称序列的连续高阶像角位移之间的直接关系。随后，我们通过在对应延迟源位置处评估每个像的贡献，将该构造扩展到圆形赤道轨道上的致密源。参考系拖曳和源运动会改变像的角位置，并在长基线可见度图案上留下独特印记。对于此处考虑的构型，这些效应作用于相反的角方向，因此最终结构由它们的竞争决定。我们的结果为在高阶像的干涉测量信号中识别黑洞自旋和源动力学的印记提供了解析框架。
英文摘要
Higher-order images produced by photons that orbit close to the unstable photon region of a black hole encode information about the spacetime geometry and leave characteristic signatures accessible with long interferometric baselines. We develop an analytical description of these signatures for a compact source in the spacetime of a slowly rotating Kerr black hole. Using the strong deflection limit, we derive the complex visibility function for a source of finite size at linear order in the black-hole spin. For a static equatorial source, we obtain a direct relation between the dimensionless Kerr spin parameter and the angular displacement of successive higher-order images belonging to the same parity sequence. We then extend the construction to a compact source on a circular equatorial orbit by evaluating each image contribution at the corresponding retarded source position. Frame dragging and source motion modify the angular positions of the images and leave distinct imprints on the long-baseline visibility pattern. For the configuration considered here, these effects act in opposite angular directions, so that the resulting structure is determined by their competition. Our results provide an analytical framework for identifying the imprints of black-hole spin and source dynamics in the interferometric signatures of higher-order images.
Comments19 pages including one appendix, 3 figures (4 subfigures)
