1306.2033 (Vyacheslav I. Dokuchaev)

Spin of the nearest supermassive black hole    [PDF]

Vyacheslav I. Dokuchaev

The Quasi-Periodic Oscillations (QPOs) of the hot plasma spots or clumps orbiting an accreting black hole contain information on the black hole mass and spin. The promising observational signatures for the measurement of black hole mass and spin are the latitudinal oscillation frequency of the bright spots in the accretion flow and the frequency of black hole horizon rotation. Both of these frequencies are independent of the accretion model and defined completely by the properties of the black hole gravitational field. Interpretation of the known QPO data by dint of signal modulation from the hot spots in the accreting plasma reveals the Kerr metric rotation parameter, a=0.64+-0.05, of the supermassive black hole in the Galactic center. At the same time, the observed 11.5 min QPO period is identified with the period of the black hole horizon rotation, and, respectively, the 19 min period is identified with the latitudinal oscillation period of hot spots in the accretion flow.

View original: http://arxiv.org/abs/1306.2033