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Dmitriy Ovchinnikov

Publications and source records attributed to Dmitriy Ovchinnikov.

4 recordsLinked to original sources

Observational signatures of misaligned double-ring and double-torus configurations around a Schwarzschild black hole

We investigate the observational signatures of an idealized double-ring and double-torus system orbiting a Schwarzschild black hole, allowing the two emitting components to have mutually inclined symmetry axes. Using general-relativistic ray tracing, we construct frequency-shift maps, bolometric flux maps on the observer's screen, and the corresponding spectral line profiles of the emitted radiation. The single equatorial torus is used as a reference configuration in order to isolate the effect of the second emitting component and of the mutual misalignment of the two structures. We show that the presence of two non-coplanar emitting structures produces characteristic multi-peak spectral profiles and asymmetric bolometric-flux distributions. These signatures are imprinted both in the line-profile morphology and in the $α$-profiles of the bolometric flux, providing simple diagnostic features of non-coplanar multi-component accretion structures.

gr-qc

Quasinormal ringing of Bardeen spacetime

We review recent calculations of quasinormal modes and asymptotic tails of the Bardeen spacetime interpreted as a quantum corrected Schwarzschild-like black holes. Massless electromagnetic and Dirac fields and massive scalar field are considered. The first few overtones are much more sensitive to the change of the quantum correction parameter than the fundamental mode, because such correction deforms the black hole geometry near the event horizon. While the asymptotic tails of massless fields are identical to those for the Schwarzschild case, the tails for a massive field differs from the Schwarzschild limit at both intermediate and asymptotic times.

gr-qc

Light curves of the hot spots on circular orbits around generic regular black holes related to non-linear electrodynamics with Maxwellian weak-field Limit

The combined effect of a strong gravitational field and electromagnetic field in the vicinity of a generic regular black hole related to non-linear electrodynamics with Maxwellian weak-field limit on the radiation flux of a hot spot orbiting the regular black hole on the Keplerian disc has been studied. The frequency shift due to the strong gravitational field and magnification of the radiation related to gravitational lensing have been calculated. We compare the flux related to the Maxwellian regular black hole to the flux of the hot spots moving with the same orbital period around standard Schwarzschild and Raissner-Nordstrom black holes to illustrate the role of the effective geometry governing photon motion around the regular black hole.

gr-qc

Shadow of the magnetically and tidally deformed black hole

We consider a simple model of a black hole surrounded by a toroidal structure and experiencing deformation due to magnetic field and the tidal force. For this system we construct the shadows of Preston-Poisson black hole, apply it to supermassive black hole $M87^*$ and compare it with the shadows of corresponding Schwarzschild and Kerr black holes. We find that for large deviation parameters $B$ and $E$ the shadow of Preston-Poisson black hole is clearly distinguishable from Kerr black hole provided the angular resolution of measurements is of order $μ\mathrm{arcsec}$.

gr-qc