An initial three-station version of the Event Horizon Telescope, a millimeter-wavelength very-long baseline interferometer, has observed Sagittarius A* (Sgr A*) repeatedly from 2007 to 2013, resulting in the measurement of a variety of interferometric quantities. Of particular importance is that there is now a large set of closure phases measured over a number of independent observing epochs. We analyze these observations within the context of a realization of semi-analytic radiatively inefficient disk models, implicated by the low luminosity of Sgr?A*. We find a broad consistency among the various observing epochs and between different interferometric data types, with the latter providing significant support for this class of model of Sgr?A*. The new data significantly tighten existing constraints on the spin magnitude and its orientation within this model context, finding a spin magnitude of , an inclination with respect to the line of sight of , and a position angle of east of north. These are in good agreement with previous analyses. Notably, the previous 180° degeneracy in the position angle has now been conclusively broken by the inclusion of the closure-phase measurements. A reflection degeneracy in the inclination remains, permitting two localizations of the spin vector orientation, one of which is in agreement with the orbital angular momentum of the infrared gas cloud G2 and the clockwise disk of young stars. This may support a relationship between Sgr?A*'s accretion flow and these larger-scale features.
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机译：Event Horizon望远镜的最初的三站式版本是毫米波长的超长基线干涉仪，从2007年到2013年，它多次观察到人马座A *（Sgr A *），从而可以测量各种干涉量。尤其重要的是，在许多独立的观测时期内，已经测出了大量封闭阶段。我们在实现半解析辐射效率低的磁盘模型的背景下分析这些观察结果，这与Sgr？A *的低发光度有关。我们发现各种观测时期之间以及不同干涉数据类型之间存在广泛的一致性，后者为此类Sgr？A *模型提供了重要支持。新数据显着收紧了在此模型上下文中对自旋幅度及其方向的现有限制，找到了的自旋幅度，相对于视线的倾斜度以及北偏东的位置角。这些与以前的分析非常吻合。值得注意的是，通过包含闭合相位测量，现在已经完全打破了先前的180°位置角简并性。仍然存在倾斜的反射简并性，允许自旋矢量方向的两个定位，其中一个与红外气体云G2的轨道角动量以及年轻恒星的顺时针方向盘一致。这可能支持Sgr？A *的吸积流量与这些较大规模的特征之间的关系。
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