THE INTRINSIC SHAPE OF SAGITTARIUS A* AT 3.5 mm WAVELENGTH
THE INTRINSIC SHAPE OF SAGITTARIUS A* AT 3.5 mm WAVELENGTH
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3.5 毫米波长下人马座 A* 的本质形状
DOI：
10.3847/0004-637x/824/1/40
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
L. Vertatschitsch
中科院分区：
文献类型：
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作者：
G. N. Ortiz;Michael D. Johnson;S. Doeleman;S. Doeleman;L. Blackburn;V. Fish;L. Loinard;L. Loinard;M. Reid;E. Castillo;A. Chael;A. Hernández;D. Hughes;J. Le'on;R. Lu;A. Montaña;G. Narayanan;K. Rosenfeld;D. S'anchez;F. Schloerb;Zhi;H. Shiokawa;J. SooHoo;L. Vertatschitsch
来自Sgr A的无线电发射被认为是由银河系中心的超大质量黑洞吸积提供动力的。在毫米波段，甚长基线干涉测量（VLBI）观测可以直接分辨出Sgr A最里面明亮的吸积区。由于在南北方向增加了许多敏感的长基线，我们在大型毫米波望远镜阿方索塞拉诺（LMT）上开发了完整的VLBI能力。我们成功地发现了Sgr A在3.5毫米的阵列组成的六个甚长基线阵列望远镜和LMT。我们将源建模为椭圆高斯亮度分布，并从闭合振幅和自校准分析中估计源的散射大小和方向，获得方法和历元之间一致的结果。然后，我们使用已知的散射内核，以确定在3.5毫米的内在的二维源的大小：，在位置角北偏东。最后，我们检测到一些基线三角形上的非零闭合相位，但我们表明，这些是一致的，被引入的折射散射在星际介质中，并不需要内在的源不对称性来解释。
The radio emission from Sgr A is thought to be powered by accretion onto a supermassive black hole of at the Galactic Center. At millimeter wavelengths, Very Long Baseline Interferometry (VLBI) observations can directly resolve the bright innermost accretion region of Sgr A . Motivated by the addition of many sensitive long baselines in the north–south direction, we developed a full VLBI capability at the Large Millimeter Telescope Alfonso Serrano (LMT). We successfully detected Sgr A at 3.5 mm with an array consisting of six Very Long Baseline Array telescopes and the LMT. We model the source as an elliptical Gaussian brightness distribution and estimate the scattered size and orientation of the source from closure amplitude and self-calibration analysis, obtaining consistent results between methods and epochs. We then use the known scattering kernel to determine the intrinsic two-dimensional source size at 3.5 mm: , at position angle east of north. Finally, we detect non-zero closure phases on some baseline triangles, but we show that these are consistent with being introduced by refractive scattering in the interstellar medium and do not require intrinsic source asymmetry to explain.