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Paper: VLBA Imaging of Sgr A* at 86 GHz
Volume: 340, Future Directions in High Resolution Astronomy: The 10th Anniversary of the VLBA
Page: 263
Authors: Shen, Z.-Q.; Lo, K.Y.; Ho, P.T.P.; Zhao, J.-H.
Abstract: We present the first VLBI image of Sgr A* ever made at 86 GHz. The image shows an E-W elongated elliptical Gaussian brightness distri-bution. By means of a model fitting procedure that makes use of the closure amplitudes, we determined the source apparent structure to be 0.21+0.02−0.01 mas by 0.13+0.05−0.13 mas with a position angle of 79°+12°−33°. There is a large error bar in the fitted minor axis size (mainly due to the poor spatial resolution along the N-S direction), but the major axis is determined very well. The discrepancy between the measured major axis size and that of the current scattering angle of 0.175 mas at 86 GHz implies an intrinsic size along E-W of 0.116 mas, or, 0.93 AU at a distance of 8 kpc.
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