Oscillation Phenomena in Sagittarius A*

We report the detection of radio QPOs with structure changes using the Very Long Baseline Array (VLBA) at 43 GHz. We found conspicuous patterned changes of the structure with P = 16.8 +/- 1.4, 22.2 +/- 1.4, 31.2 +/- 1.5, 56.4 +/- 6 min very roughly in a 3 : 4 : 6 : 10 ratio. The first two periods show a rotating one-arm structure, while the P = 31.4 min shows a rotating 3-arm structure, as if viewed edge-on. At the central 50 mu as the P = 56.4 mm period shows a double amplitude variation of those in its surroundings. Spatial distributions of the oscillation periods suggest that the disk of SgrA* is roughly edge-on, rotating around an axis with PA = -10 degrees. Presumably, the observed VLBI images of SgrA* at 43 GHz retain several features of the black hole accretion disk of SgrA* in spite of being obscured and broadened by scattering of surrounding plasma.