论文标题
肢体亮度的细节首次揭示了射流底部的结构，第87次
The Details of Limb Brightening Reveal the Structure of the Base of the Jet in M\,87 for the First Time
论文作者
论文摘要
它已经变得司空见惯的是天文学，可以根据parsec尺度性能的讨论来描述以宽松定义的术语（例如“鞘”和“脊柱”）的横向粗糙结构。但是，这些特征在亚LT-hyr量表上的适用性，维度和突出性先前已被观察不受限制。 M \ 87中源附近的射流结构的第一个直接证据是极端的肢体亮度（一种双轨形态），来自源的0.3-0.6 MAS，这在具有高分辨率和灵敏度的观察结果中是突出的。这些图像的强度交叉切割对负责双轨形态的几何形状提供了三个强，相互依存的约束：导轨与轨道分离，峰值与槽强度比和导轨宽度。分析这些约束表明，一半或更多的射流体积位于厚的，管状的，轻度相对论的，质子射流仅$ \ sim 0.25 $ lt-yr（或$ \ sim 300 $ 300 $ 300 $ m），其中m是来自源代码的中央黑洞质量）。相比之下，事件地平线望远镜协作借助一般相对论的磁性水力动力学模拟来解释其观察结果，这些模拟产生了带有周围发光，薄鞘的隐形（通过构造）射流。然而，结果表明，模拟喷气机的合成图像是从源中的0.3-0.6 MAS亮了。这种与观察的严重分离发生在先前声称的文献中以模拟为代表的区域。肢体亮度分析激发了对可能的模拟修改的讨论，以提高与观察的一致性。
It has become commonplace is astronomy to describe the transverse coarse structure of jets in loosely defined terms such as "sheath" and "spine" based on discussions of parsec scale properties. But, the applicability, dimension and prominence of these features on sub-lt-yr scales has previously been unconstrained by observation. The first direct evidence of jet structure near the source in M\,87 is extreme limb brightening (a double-rail morphology), 0.3 - 0.6 mas from the source, that is prominent in observations with high resolution and sensitivity. Intensity cross-cuts of these images provide three strong, interdependent constraints on the geometry responsible for the double-rail morphology: the rail to rail separation, the peak to trough intensity ratio and the rail widths. Analyzing these constraints indicates that half or more of the jet volume resides in a thick-walled, tubular, mildly relativistic, protonic jet only $\sim 0.25$ lt-yr (or $\sim 300$ M, where M is the central black hole mass in geometrized units) from the source. By contrast, the Event Horizon Telescope Collaboration interprets their observations with the aid of general relativistic magnetohydrodynamic simulations that produce an invisible (by construction) jet with a surrounding luminous, thin sheath. Yet, it is shown that synthetic images of simulated jets are center brightened 0.3 - 0.6 mas from the source. This serious disconnection with observation occurs in a region previously claimed in the literature to be well represented by the simulations. The limb brightening analysis motivates a discussion of possible simulation modifications to improve conformance with observations.
