ALMA Memo May An Approach Detecting the Event Horizon of SgrA

Imaging the vicinity of a black hole is one of the ultimate goals of VLBI astronomy The closest massive black hole SgrA located at the Galactic center is the leading candidate for such observations Combined with recent VLBI recording technique and submillimeter radio engineering we now have the su cient sensitivity for the observations Here we show performance simulations of submillimeter VLBI arrays for imaging SgrA Good images are obtained from submillimeter VLBI arrays in the southern hemisphere composed of more than stations We also note that even with a small array we can estimate the shadow size and then the mass of black hole from visibility analysis Now all we need is to construct a submillimeter VLBI array in the southern hemisphere if we wish to unveil the black hole environment of SgrA