223 citations · 1.2k across the 39 of their papers we have counts for
39 papers
Boson Stars surrounded by Polish Doughnuts in Scalar-Tensor Theory
Kristian Gjorgjieski, Maxim Rose, Burkhard Kleihaus +2
We investigate thick accretion disks (Polish Doughnuts) around rotating self-interacting boson stars in general relativity and scalar-tensor theories, focusing on spontaneously sca…
Polarized Equatorial Emission around Kerr Black Holes with Synchronized Scalar Hair. I. Direct images
Valentin O. Deliyski, Galin N. Gyulchev, Daniela D. Doneva +2
We investigate the polarization properties of the direct images of a geometrically and optically thin accretion disk around fully self-consistent models of rotating Kerr black hole…
Images of the Thin Accretion Disk Around Kerr Black Holes coupled to time periodic scalar fields
Galin N. Gyulchev, Daniela D. Doneva, Valentin O. Deliyski +2
We investigate the orbital structure and observable appearance of rotating Kerr black holes endowed with synchronized scalar hair described by two time-periodic scalar fields with…
Shadows of rotating traversable wormholes surrounded by plasma
Tsanimir Angelov, Rasim Bekir, Galin Gyulchev +2
We study the influence of the plasma environment on the shadows of stationary axisymmetric wormholes. We consider a sample of several wormhole solutions and plasma distributions fo…
Matter Accumulations and Accretion Tori around Wormholes
Kristian Gjorgjieski, Jutta Kunz, Petya Nedkova
We study circular orbits and accretion structures around symmetric wormholes. As exemplary solutions we choose three different wormhole spacetimes, namely rotating traversable worm…
Circular Orbits and Photon Orbits at Wormhole Throats
Kristian Gjorgjieski, Jutta Kunz, Petya Nedkova
In this work we study timelike circular orbits and photon orbits at the throat of stationary and axisymmetric wormholes. Our minimal requirements on the spacetime are the existence…
Polarized equatorial emission and hot spots around black holes with a dark matter halo
Tsanimir Angelov, Rasim Bekir, Galin Gyulchev +2
We study the linear polarization of the accretion disk around black holes with a dark matter halo. The interaction of the black hole with the dark matter is modelled by considering…
Parameter Constraints on Traversable Wormholes within Beyond Horndeski Theories through Quasi-Periodic Oscillations
Farukh Abdulkhamidov, Petya Nedkova, Javlon Rayibaev +2
{\it Hunting} compact astrophysical objects such as black holes and wormholes, as well as testing gravity theories, are important issues in relativistic astrophysics. In this sense…
Comparison of Magnetized Thick Disks around Black Holes and Boson Stars
Kristian Gjorgjieski, Jutta Kunz, Petya Nedkova
Boson stars are considered as promising candidates for black hole mimickers. Similar to other compact objects they can form accretion disks around them. The properties of these dis…
Shadows of rotating hairy Kerr black holes coupled to time periodic scalar fields with non-flat target space
Galin N. Gyulchev, Ayush Roy, Lucas G. Collodel +3
We study the shadows cast by rotating hairy black holes with two non-trivial time-periodic scalar fields having a non-flat Gaussian curvature of the target space spanned by the sca…
Observing naked singularities by the present and next-generation Event Horizon Telescope
Valentin Deliyski, Galin Gyulchev, Petya Nedkova +1
We consider the observational signatures of reflective naked singularities as seen by the current and next-generation Event Horizon Telescope (EHT). The reflective naked singularit…
Polarized image of equatorial emission in horizonless spacetimes: naked singularities
Valentin Deliyski, Galin Gyulchev, Petya Nedkova +1
We study the linear polarization from the accretion disk around weakly and strongly naked Janis-Newman-Winicour singularities. We consider an analytical toy model of thin magnetize…
Magnetized Thick Disks around Boson Stars
Kristian Gjorgjieski, Jutta Kunz, Matheus C. Teodoro +2
The effects of magnetic fields on accretion disks around compact objects are of high importance in the study of their general properties and dynamics. Here we analyze the influence…
Polarized image of equatorial emission in horizonless spacetimes I: traversable wormholes
Valentin Delijski, Galin Gyulchev, Petya Nedkova +1
We study the linear polarization from the accretion disk around a class of static traversable wormholes. Applying the simplified model of a magnetized fluid ring orbiting in the eq…
Photon surfaces, shadows and accretion disks in gravity with minimally coupled scalar field
Igor Bogush, Dmitri Gal'tsov, Galin Gyulchev +3
In this article, we conduct a sequential study of possible observable images of black hole simulators described by two recently obtained rotating geometries in Einstein gravity, mi…
Axial perturbations of hairy Gauss-Bonnet black holes with massive self-interacting scalar field
Kalin V. Staykov, Jose Luis Blázquez-Salcedo, Daniela D. Doneva +3
We study the axial quasinormal modes of hairy black holes in Gauss-Bonnet gravity with massive self-interacting scalar field. Two coupling functions of the scalar field to the Gaus…
Polish Doughnuts around Scalarized Kerr Black Holes
Matheus C. Teodoro, Lucas G. Collodel, Daniela Doneva +3
In this work we aim to investigate non-mainstream thick tori configurations around Kerr Black Holes with Scalar Hair (KBHsSH). For that goal, we provide a first approach using cons…
Quasi-periodic Oscillations in Rotating Ellis Wormhole Spacetimes
Efthimia Deligianni, Burkhard Kleihaus, Jutta Kunz +2
We analyze the properties of the circular orbits for massive particles in the equatorial plane of symmetric rotating Ellis wormholes. In particular, we obtain the orbital frequenci…
Image of the thin accretion disk around compact objects in the Einstein-Gauss-Bonnet gravity
Galin Gyulchev, Petya Nedkova, Tsvetan Vetsov +1
We study the optical appearance of a thin accretion disk around compact objects within the Einstein-Gauss-Bonnet gravity. Considering static spherically symmetric black holes and n…
Quasi-periodic oscillations from the accretion disk around rotating traversable wormholes
Efthimia Deligianni, Jutta Kunz, Petya Nedkova +2
We study the quasi-periodic oscillations from the accretion disk around rotating traversable wormholes by means of the resonance models. We investigate the linear stability of the…
Polar quasinormal modes of the scalarized Einstein-Gauss-Bonnet black holes
Jose Luis Blázquez-Salcedo, Daniela D. Doneva, Sarah Kahlen +3
We study the polar quasinormal modes of spontaneously scalarized black holes in Einstein-Gauss-Bonnet theory. In previous works we showed that a set of nodeless solutions of the fu…
Observational signatures of strongly naked singularities: image of the thin accretion disk
Galin Gyulchev, Jutta Kunz, Petya Nedkova +2
We study the optical appearance of a thin accretion disk around the strongly naked static Janis-Newman-Winicour singularity. The solution does not possess a photon sphere, which re…
Axial perturbations of the scalarized Einstein-Gauss-Bonnet black holes
Jose Luis Blázquez-Salcedo, Daniela D. Doneva, Sarah Kahlen +3
We study the axial perturbations of spontaneously scalarized black holes in Einstein-Gauss-Bonnet (EGB) theories. We consider the nodeless solutions of the fundamental branch of th…
Quasi-periodic oscillations from the accretion disk around distorted black holes
Efthimia Deligianni, Jutta Kunz, Petya Nedkova
We study the quasi-periodic oscillations from the accretion disk around the distorted Schwarzschild black hole in the framework of the resonant models. We confine ourselves to the…