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| Paper: |
Oscillation Phenomena in Sagittarius A* |
| Volume: |
439, The Galactic Center: a Window to the Nuclear Environment of Disk Galaxies |
| Page: |
336 |
| Authors: |
Miyoshi, M.; Oyama, T.; Shen, Z.; Takahashi, R.; Kato, Y. |
| 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 ± 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 50μ as 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°.
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. |
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