X-ray reflection spectroscopy (or iron line method) is a powerful tool to probe the strong gravity region of black holes, and currently is the only technique for measuring the spin of the supermassive ones. While all the available relativistic reflection models assume thin accretion disks, we know that several sources accrete near or above the Eddington limit and therefore must have thick accretion disks. In this work, we employ the Polish donut model for the description of thick disks. We thus estimate the systematic error on the spin measurement when a source with a thick accretion disk is fitted with a thin disk model. Our results clearly show that spin measurements can be significantly affected by the morphology of the accretion disk. Current spin measurements of sources with high mass accretion rate are therefore not reliable.

中文翻译：

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模拟超大质量黑洞自旋测量中的偏差

X射线反射光谱法（或铁线法）是探测黑洞强引力区的有力工具，也是目前唯一测量超大质量黑洞自旋的技术。虽然所有可用的相对论反射模型都假设吸积盘很薄，但我们知道有几个源在爱丁顿极限附近或以上吸积，因此必须有厚吸积盘。在这项工作中，我们使用波兰甜甜圈模型来描述厚盘。因此，当具有厚吸积盘的源配备薄吸积盘模型时，我们估计了自旋测量的系统误差。我们的结果清楚地表明，吸积盘的形态会显着影响自旋测量。因此，具有高质量吸积率的源的当前自旋测量是不可靠的。