利用旋转对称性判别M87的吸积态
Discriminating Accretion States via Rotational Symmetry in Simulated Polarimetric Images of M87
摘要：
2017年4月，事件视界望远镜观测到椭圆星系梅西耶87核心的超大质量黑洞阴影。虽然原始图像是根据总强度的测量构建的，但也收集了完整的偏振数据，预计在不久的将来会有线性偏振图像。我们提出了一种模式图像分解的线性极化场的基函数与不同的方位角依赖的电矢量的位置角。我们应用这种分解的图像的射线跟踪广义相对论磁流体力学模拟的Messier 87吸积盘。对于物理上与以前的观测结果一致的模拟图像，与旋转对称性相关的系数$β_2$的大小是吸积状态之间的有用的距离。我们发现，在20 $μ$的分辨率，$|β_2|$是大于0.2，只有模型的磁盘水平尺度的磁压力大到足以破坏稳定的吸积。我们还发现，具有更多的径向电矢量位置角的图像对应于具有更高的黑洞自旋的模型。我们的分析表明，建议的分解作为一个诊断框架，以提高理论模型的约束的效用。
英文摘要：
In April 2017, the Event Horizon Telescope observed the shadow of the supermassive black hole at the core of the elliptical galaxy Messier 87. While the original image was constructed from measurements of the total intensity, full polarimetric data were also collected, and linear polarimetric images are expected in the near future. We propose a modal image decomposition of the linear polarization field into basis functions with varying azimuthal dependence of the electric vector position angle. We apply this decomposition to images of ray traced general relativistic magnetohydrodynamics simulations of the Messier 87 accretion disk. For simulated images that are physically consistent with previous observations, the magnitude of the coefficient associated with rotational symmetry, $β_2$, is a useful discriminator between accretion states. We find that at 20 $μ$as resolution, $|β_2|$ is greater than 0.2 only for models of disks with horizon-scale magnetic pressures large enough to disrupt steady accretion. We also find that images with a more radially directed electric vector position angle correspond to models with higher black hole spin. Our analysis demonstrates the utility of the proposed decomposition as a diagnostic framework to improve constraints on theoretical models.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
