Correlations between the development of a flare in the Blazar 3C 454.3 in the radio and optical

Abstract

Radio and optical data are used to analyze the development of the flare in the blazar 3C 454.3 observed in 2004–2007. A detailed
correspondance between the optical and radio flares is established, with a time delay that depends on the observing frequency.
The variation of the delay of the radio flare relative to the optical flare is opposite to the dispersion delay expected for
the propagation of radiation in the interstellar medium, testifying to an intrinsic origin for the observed outburst. Small-scale
flux variations on time intervals of 5–10 days in the millimeter and optical are also correlated, with a time delay of about
ten months. This may provide evidence for a single source generating the radiation at all wavelengths. Rapid flux fluctuations
in the radio and optical that are correlated with the indicated time delays could be associated with inhomogeneities in the
accretion disk. Detailed studies of the flux variations of Active Galactic Nuclei (AGN) can be used to analyze the structure
of the accretion disk. A model for the energy release in AGN that is not associated purely with accretion onto supermassive
black holes is proposed. As is the case for other active members of the AGN family, estimates of the lifetime of the binary
black-hole system in 3C 454.3 suggest that this object is in a stage of its evolution that is fairly close to the coalescence
of its black holes. The energy that is released as the companion of the central black hole loses orbital angular momentum
is sufficient to explain the observed AGN phenomena. The source of primary energy release could be heating of the gas behind
shock fronts that arise due to the friction between the companion black hole and the ambient gaseous medium. The orbit of
the companion could be located at the periphery of the accretion disk of the central body at its apocenter and plunge more
deeply into the accretion disk at its pericenter, inducing flares at all wavelengths. Energy-release parameters such as the
temperature and density of the heated gas are estimated for 3C 454.3. The model considered assumes omnidirectional radiation
of the medium in the presence of a magnetic field. The radiation corresponding to the minimum flux level (base level) could
represent omnidirectional radiation due to the orbit of the moving companion. The fraction of the energy that is transferred
to directed jets is small, comprising 1–2% of the total energy released due to the loss of orbital angular momentum by the
companion.