1998A&A...335L.106K

We have observed and detected SgrA* with VLBI at 86GHz and at 215GHz in March 1995. At 86GHz the measured closure phase is close to zero, consistent with a point-like or symmetric structure of 190±30µas in size. At 215GHz we have detected SgrA* with a signal-to-noise ratio of 6. This yields a tentative size estimate of 110±60µas which, despite of a limited calibration accuracy and uncertainty in the origin of the mm/sub-mm total flux density excess, lies well above the scattering size of 20µas at this frequency. The intrinsic size of SgrA* thus appears to be 17±9 Schwarzschild radii for a 2.6x10⁶M_☉ black hole.