| Oscillation Phenomena in the disk around the massive black hole Sagittarius A* (2009) | |||||||||
Abstract | |||||||||
| 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, 22.2, 31.4, & 56.4 min, 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* remain several features of the black hole accretion disk of SgrA* in spite of being obscured and broadened by scattering of surrounding plasma.. Comment: 5 pages, 3 figures, submitted to MN Letter | |||||||||
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