Oscillation phenomena in the disk around the massive black hole
نویسندگان
چکیده
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 50μas 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 Sgr A∗ is roughly edgeon, rotating around an axis with PA = −10◦. Presumably, the observed VLBI images of Sgr A∗ remain several features of the black hole accretion disk of Sgr A∗ in spite of being obscured and broadened by scattering of surrounding plasma.
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