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 microasec the P = 56.4 min 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 degree. 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.Comment: 24 pages, 20 figures, revised version submitted to MN main journal
(2010, Jan., 12th
