2021A&A...648A..27V

Aims. A new method for determining the parameters of close double systems of supermassive black holes is proposed.
Methods. We used the ground-based radio telescope in Simeiz (RT-22). Observational data were collected and processed automatically. Harmonic and wavelet data analyses were used to find the components of changes in the flux densities of 3C 454.3.
Results. 3C 454.3 may be the most massive double system in the Universe. We show that when the bulk Lorentz (γ-factor) is taken into account, it is possible to obtain the agreed parameters of the 3C 454.3. We present first estimates of the size and thickness of the accretion disk of the 3C 454.3 obtained directly from the observation data. Based on the obtained data, we consider the characteristics of the gravitational radiation of this system, as well as the lifetime before merging, and possible variations in companion orbits.