27 citations · 158 across the 22 of their papers we have counts for
25 papers · 1 filter
Regular Reissner--Nordström--de Sitter Black Holes: Thin-Shell Matching and Modified Density Profiles
Reza Saadati, Yu Shi, Vitalii Vertogradov
We investigate two distinct approaches to regularizing the central singularity of the Reissner--Nordström--de Sitter geometry. In the first approach, a de Sitter interior is matche…
Effective Matter Conversion in Gravitational Collapse and the Dynamical Formation of Regular Black Holes
Emmanuele Battista, Ali Ovgun, Vitalii Vertogradov
We study inverse source reconstruction in generalized Vaidya spacetimes. A prescribed density fixes the mass and tangential pressure, while a two-sector decomposition determines a…
Black hole and wormhole branches in gravitational decoupling
Francisco Tello-Ortiz, Y. Gomez-Leyton, Vitalii Vertogradov +1
Minimal Geometric Deformation (MGD) applied to a static Schwarzschild black hole seed generates a single decoupler function , obtained by solving the -sector field equatio…
Optical-area minimum method for static spherical black hole shadows
Vitalii Vertogradov, Nikko John Leo S. Lobos, Ali Ovgun +1
We formulate a global optical-area method for shadows of static, spherically symmetric black holes. For the metric \(ds^{2}=-A(r)dt^{2}+B(r)dr^{2}+C(r)dΩ^{2}\), spherical sections…
Shadow of the generalized Vaidya black hole
Vitalii Vertogradov, Ali Övgün
In this paper, we investigate the shadow of the generalized Vaidya black hole described by the Husain solution. Assuming a barotropic equation of state for the additional matter se…
Regular Black Hole Formation and Gamma-Ray Burst from Matter Conversion
Vitalii Vertogradov, Zhanna Kuznetsova, Yu Shi
During the gravitational collapse of a massive star into a regular black hole, a new form of matter must be produced in order to prevent the formation of a central singularity. Sin…
Exact Dynamical Regular Black Holes from Generalized Polytropic Matter
Dmitriy Kudryavcev, Yi Ling, Vitalii Vertogradov
We present a class of exact, dynamical, and fully analytic solutions describing regular black holes formed via the gravitational collapse of matter obeying a generalized polytropic…
Interplay of Null Energy Condition Violations and Thermodynamics in Kiselev Black Hole Evaporation
Vitalii Vertogradov, Maksim Grigorev
The evaporation of black holes with two horizons presents a rich thermodynamic landscape that departs fundamentally from the Schwarzschild paradigm. In this work, we analyze the Ha…
Energy Extraction and Evolution of Regular Black Holes: The Case of Bardeen Spacetime
Vitalii Vertogradov, Angel Rincon
This paper examines regular black holes, in particular the Bardeen spacetime where singularities are replaced by non-singular cores. It explores the energy extraction through the c…
Barotropic Equation of State and Nonlinear Electrodynamics in Dynamical Black Hole Spacetimes
Vitalii Vertogradov, Dmitriy Kudryavtcev
Models of black holes that differ from idealized vacuum and electrovacuum solutions of Einstein's equations often contain parameters whose physical interpretation is unclear. Howev…
Gravitational Collapse and Formation of Regular Black Holes: Dymnikova, Hayward, and Beyond
Vitalii Vertogradov
The gravitational collapse of a star can lead to the formation of a regular black hole. However, a key factor in this process is the transition of ordinary baryonic matter into a s…
Regular Black Hole Models in the Transition from Baryonic Matter to Quark Matter
Vitalii Vertogradov, Ali Övgün
In this paper, we investigate gravitational collapse scenarios involving baryonic matter transitioning into quark-gluon plasma under extreme astrophysical conditions, focusing on t…
Formation of regular black hole from baryonic matter
Vitalii Vertogradov, Ali Övgün, Daniil Shatov
We present a family of exact, singularity-free solutions describing the collapse of baryonic matter characterized by a barotropic equation of state whose coefficient varie…
Analytical approach for calculating shadow of dynamical black hole
Vitalii Vertogradov, Ali Övgün
We develop a compact and transparent framework for photon dynamics and shadow formation in slowly evolving, spherically symmetric spacetimes. Starting from the Eddington-Finkelstei…
Signatures of a de Sitter-core black hole in ringing, transmission and optical appearance
N. Heidari, A. A. Araújo Filho, V. Vertogradov and +1
We investigate a static, asymptotically flat black hole whose central region approaches a de Sitter vacuum. The geometry is controlled by the ADM mass and a core scale , a…
Dynamical Black Holes: Apparent Horizon Versus Energy Conditions
Vitalii Vertogradov
Dynamical black holes have an apparent horizon as one of their characteristics. The later might be null, time-like, or space-like surfaces that define the evolution of a black hole…
Exact Regular Black Hole Solutions with de Sitter Cores and Hagedorn Fluid
Vitalii Vertogradov, Ali Övgün
In this paper, we present three exact solutions to the Einstein field equations, each illustrating different black hole models. The first solution introduces a black hole with a va…
General Approach on Shadow Radius and Photon Spheres in Asymptotically Flat Spacetimes and the Impact of Mass-Dependent Variations
Vitalii Vertogradov, Ali Övgün
Recent observations of black hole shadows have revolutionized our ability to probe gravity in extreme environments. This manuscript presents a novel analytic method to calculate, i…
Analyzing the Influence of Geometrical Deformation on Photon Sphere and Shadow Radius: A New Analytical Approach -- Spherically Symmetric Spacetimes
Vitalii Vertogradov, Ali Övgün
In this paper, we introduce a new approach to study the behavior of the photon sphere and shadow radius. Our method uses extended gravitational decoupling and reveals two important…
Non-singular black hole by gravitational decoupling and some thermodynamic properties
Maxim Misyura, Angel Rincon, Vitalii Vertogradov
Gravitational decoupling allows to obtain new solutions of general relativity. In this paper, we obtain new solutions of the Einstein field equations which describe non-singular bl…
Analyzing the Influence of Geometrical Deformation on Photon Sphere and Shadow Radius: A New Analytical Approach -Stationary, and Axisymmetric Spacetime
Vitalii Vertogradov, Ali Övgün, Reggie C. Pantig
Black hole shadows and photon spheres offer valuable tools for investigating black hole properties. Recent observations by the Event Horizon Telescope Collaboration have confirmed…
Influence of primary hair and plasma on intensity distribution of black hole shadows
Vitalii Vertogradov, Maxim Misyura, Parth Bambhaniya
In this paper, we investigate the influence of primary hair () on the shadows of hairy Schwarzschild and Reissner-Nordström black holes obtained through gravitational decoupling…
Dynamical Photon Spheres in Charged Black Holes and Naked Singularities
Yaghoub Heydarzade, Vitalii Vertogradov
To understand the nature of a black hole shadow in dynamical spacetimes, we construct an analytical model of a dynamical photon sphere in the context of the Bonnor-Vaidya spacetime…
Hairy Kiselev Black Hole Solutions
Yaghoub Heydarzade, Maxim Misyura, Vitalii Vertogradov
In the realm of astrophysics, black holes exist within nonvacuum cosmological backgrounds, making it crucial to investigate how these backgrounds influence the properties of black…