Zobrazeno 1 - 10
of 478
pro vyhledávání: '"Yazadjiev, Stoytcho"'
Scalar-Gauss-Bonnet (sGB) gravity with an additional coupling between the scalar field and the Ricci scalar exhibits very interesting properties related to black hole stability, evasion of binary pulsar constraints, and general relativity as a late-t
Externí odkaz:
http://arxiv.org/abs/2404.15526
Publikováno v:
Phys.Rev.D 109 (2024) 12, 124064
In this paper, we apply a novel approach based on physics-informed neural networks to the computation of quasinormal modes of black hole solutions in modified gravity. In particular, we focus on the case of Einstein-scalar-Gauss-Bonnet theory, with s
Externí odkaz:
http://arxiv.org/abs/2404.11583
Autor:
Babichev, Eugeny, Charmousis, Christos, Doneva, Daniela D., Gyulchev, Galin N., Yazadjiev, Stoytcho S.
There is strong observational evidence that almost every large galaxy has a supermassive black hole at its center. It is of fundamental importance to know whether such black holes are described by the standard Kerr solution in General Relativity (GR)
Externí odkaz:
http://arxiv.org/abs/2403.16192
Autor:
Gyulchev, Galin N., Roy, Ayush, Collodel, Lucas G., Nedkova, Petya G., Yazadjiev, Stoytcho S., Doneva, Daniela D.
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 scalar fields. Such black holes are a viable alternative to the Kerr blac
Externí odkaz:
http://arxiv.org/abs/2402.08469
Publikováno v:
A&A 687, A17 (2024)
Binary pulsars are a powerful tool for probing strong gravity that still outperforms direct gravitational wave observations in a number of directions due to the remarkable accuracy of the pulsar timing. They can constrain very precisely the presence
Externí odkaz:
http://arxiv.org/abs/2402.06305
We consider the observational signatures of reflective naked singularities as seen by the current and next-generation Event Horizon Telescope (EHT). The reflective naked singularities lead to a distinctive morphology of their accretion disk images pr
Externí odkaz:
http://arxiv.org/abs/2401.14092
Autor:
Yazadjiev, Stoytcho, Doneva, Daniela
We prove under certain weak assumptions a black hole no-hair theorem in spherically symmetric spacetimes for self-gravitating time-dependent multiple scalar fields with an arbitrary target space admitting a Killing field with a non-empty axis and arb
Externí odkaz:
http://arxiv.org/abs/2401.13288
Autor:
Bahamonde, Sebastian, Doneva, Daniela D., Ducobu, Ludovic, Pfeifer, Christian, Yazadjiev, Stoytcho S.
Publikováno v:
Phys.Rev.D 108 (2023), 064044
We examine the teleparallel formulation of non-minimally coupled scalar Einstein-Gauss-Bonnet gravity. In the teleparallel formulation, gravity is described by torsion instead of curvature, causing the usual Gauss-Bonnet invariant expressed through c
Externí odkaz:
http://arxiv.org/abs/2307.14720
Autor:
Doneva, Daniela D., Saló, Llibert Aresté, Clough, Katy, Figueras, Pau, Yazadjiev, Stoytcho S.
Quadratic theories of gravity with second order equations of motion provide an interesting model for testing deviations from general relativity in the strong gravity regime. However, they can suffer from a loss of hyperbolicity, even for initial data
Externí odkaz:
http://arxiv.org/abs/2307.06474
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 magnetized fluid ring orbiting in the equatorial plane and emitting synchrotron
Externí odkaz:
http://arxiv.org/abs/2303.14756