发表机构
Shanghai University; Fuzhou University; National University of Uzbekistan; Kimyo International University in Tashkent; Tashkent State Technical University（上海大学; 福州大学; 乌兹别克斯坦国立大学; 塔什干基莫国际大学; 塔什干国立技术大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究构建了STVG中由PFDM环绕的旋转黑洞模型，分析其阴影、能量发射与eikonal准正则模，并与M87*和Sgr A*观测对比，揭示了PFDM对参数空间的影响及自旋对模式分离的作用。
AI 中文摘要
我们研究了标量-张量-矢量引力（STVG）中由完美流体暗物质（PFDM）环绕的旋转黑洞的光学和动力学性质。从静态STVG-PFDM几何出发，我们考虑了一个类Kerr的旋转扩展，其特征由自旋参数$a$、STVG耦合参数$\alpha$和PFDM参数$\lambda$描述。我们首先检查了视界结构和径向有效质量函数，然后分析了零测地线和不稳定球面光子轨道。我们利用这些结果构建了黑洞阴影，并研究了其大小、畸变以及对模型参数和观测者倾角的依赖性。然后，在$(a,\alpha)$参数空间中，针对PFDM参数的代表值，我们将预测的角阴影直径与事件视界望远镜对M87$^*$和Sgr A$^*$的观测进行了比较。比较表明，PFDM的贡献可以移动与观测阴影直径兼容的参数空间区域，而阴影大小对自旋的敏感性通常低于对形变的敏感性。我们进一步在高频几何光学近似下，利用阴影半径作为有效吸收尺度，估计了霍金能量发射谱。最后，我们通过不稳定光子轨道与振铃频率之间的对应关系，研究了eikonal极限下的准正则模谱。数值结果恢复了预期的Schwarzschild极限，并显示出随着自旋增加，顺行和逆行模式之间的清晰分离。综合分析为旋转STVG-PFDM几何提供了一致的光学、能量发射和振铃表征。
英文摘要
We investigate the optical and dynamical properties of a rotating black hole in scalar--tensor--vector gravity (STVG) surrounded by perfect fluid dark matter (PFDM). Starting from the static STVG--PFDM geometry, we consider a Kerr-like rotating extension characterized by the spin parameter $a$, the STVG coupling $α$, and the PFDM parameter $λ$. We first examine the horizon structure and a radial effective mass function, then analyze null geodesics and unstable spherical photon orbits. We use these results to construct the black-hole shadow and study its size, distortion, and dependence on model parameters and observer inclination. We then compare the predicted angular shadow diameter with the Event Horizon Telescope observations of M87$^*$ and Sgr~A$^*$ in the $(a,α)$ parameter space for representative values of the PFDM parameter. The comparison shows that the PFDM contribution can shift the parameter-space region compatible with the observed shadow diameter, while the shadow size is generally less sensitive to spin than to deformation. We further estimate the Hawking energy-emission spectrum in the high-frequency geometric-optics approximation, using the shadow radius as an effective absorption scale. Finally, we study the quasinormal-mode spectrum in the eikonal limit through the correspondence between unstable photon orbits and ringdown frequencies. The numerical results recover the expected Schwarzschild limit and show a clear separation between the prograde and retrograde modes as the spin increases. The combined analysis provides a consistent optical, energy emission, and ringdown characterization of the rotating STVG--PFDM geometry.
Comments18 pages, 14 figures
