2013/06/30 by Vyacheslav I. Dokuchaev · 3 citations
Physics and Astronomy · #Accretion (finance) #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Binary black hole #Black hole (networking) #Event horizon #Intermediate-mass black hole #Relativity and Gravitational Theory #Spin-flip #Stellar black hole #Supermassive black hole #astro-ph.HE #gr-qc
paper · pdf · doi:10.1007/s10714-014-1832-x
published as Gen. Relativ. Gravit. 46, 1832 (2014) · 13 pages, 8 figures, added references
openalex publication_date 2014/11/07 · arxiv created 2014/11/28 · arxiv updated 2014/12/02 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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 event 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 a signal modulation from the hot spots in the accreting plasma reveals the Kerr metric rotation parameter, a=0.65±0.05, and mass, M=(4.2±0.2)106M_\odot, of the supermassive black hole in the Galactic center. At the same time, the observed 11.5 min QPO period is identified with a period of the black hole event horizon rotation, and, respectively, the 19 min period is identified with a latitudinal oscillation period of hot spots in the accretion flow. The described approach is applicable to black holes with a low accretion rate, when accreting plasma is transparent up to the event horizon region.