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Kuan HJ, Suvorov AG, Doneva DD, Yazadjiev SS. Gravitational Waves from Accretion-Induced Descalarization in Massive Scalar-Tensor Theory. Phys Rev Lett 2022; 129:121104. [PMID: 36179164 DOI: 10.1103/physrevlett.129.121104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 07/05/2022] [Accepted: 08/30/2022] [Indexed: 06/16/2023]
Abstract
Many classes of extended scalar-tensor theories predict that dynamical instabilities can take place at high energies, leading to the formation of scalarized neutron stars. Depending on the theory parameters, stars in a scalarized state can form a solution-space branch that shares a lot of similarities with the so-called mass twins in general relativity appearing for equations of state containing first-order phase transitions. Members of this scalarized branch have a lower maximum mass and central energy density compared to Einstein ones. In such cases, a scalarized star could potentially overaccrete beyond the critical mass limit, thus triggering a gravitational phase transition where the star sheds its scalar hair and migrates over to its nonscalarized counterpart. Such an event resembles, but is distinct from, a nuclear or thermodynamic phase transition. We dynamically track a gravitational transition by first constructing hydrostatic, scalarized equilibria for realistic equations of state, and then allowing additional material to fall onto the stellar surface. The resulting bursts of monopolar radiation are dispersively stretched to form a quasicontinuous signal that persists for decades, carrying strains of order ≳10^{-22} (kpc/L)^{3/2} Hz^{-1/2} at frequencies of ≲300 Hz, detectable with the existing interferometer network out to distances of L≲10 kpc, and out to a few hundred kpc with the inclusion of the Einstein Telescope. Electromagnetic signatures of such events, involving gamma-ray and neutrino bursts, are also considered.
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Affiliation(s)
- Hao-Jui Kuan
- Theoretical Astrophysics, Eberhard Karls University of Tübingen, Tübingen 72076, Germany
- Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Arthur G Suvorov
- Theoretical Astrophysics, Eberhard Karls University of Tübingen, Tübingen 72076, Germany
- Manly Astrophysics, 15/41-42 East Esplanade, Manly, NSW 2095, Australia
| | - Daniela D Doneva
- Theoretical Astrophysics, Eberhard Karls University of Tübingen, Tübingen 72076, Germany
- INRNE-Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria
| | - Stoytcho S Yazadjiev
- Theoretical Astrophysics, Eberhard Karls University of Tübingen, Tübingen 72076, Germany
- Department of Theoretical Physics, Faculty of Physics, Sofia University, Sofia 1164, Bulgaria
- Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, Acad. G. Bonchev St. 8, Sofia 1113, Bulgaria
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Blázquez-Salcedo JL, Doneva DD, Kunz J, Yazadjiev SS. Radial perturbations of scalar-Gauss-Bonnet black holes beyond spontaneous scalarization. Int J Clin Exp Med 2022. [DOI: 10.1103/physrevd.105.124005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Kuan HJ, Doneva DD, Yazadjiev SS. Dynamical Formation of Scalarized Black Holes and Neutron Stars through Stellar Core Collapse. Phys Rev Lett 2021; 127:161103. [PMID: 34723617 DOI: 10.1103/physrevlett.127.161103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 08/06/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
In a certain class of scalar-Gauss-Bonnet gravity, the black holes and the neutron stars can undergo spontaneous scalarization-a strong gravity phase transition triggered by a tachyonic instability due to the nonminimal coupling between the scalar field and the spacetime curvature. Studies of this phenomenon have, so far, been restricted mainly to the study of the tachyonic instability and stationary scalarized black holes and neutron stars. To date, no realistic physical mechanism for the formation of isolated scalarized black holes and neutron stars has been proposed. We study, for the first time, the spherically symmetric fully nonlinear stellar core collapse to a black hole and a neutron star in scalar-Gauss-Bonnet theories allowing for a spontaneous scalarization. We show that the core collapse can produce scalarized black holes and scalarized neutron stars starting with a nonscalarized progenitor star. The possible paths to reach the end (non)scalarized state are quite rich leading to interesting possibilities for observational manifestations.
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Affiliation(s)
- Hao-Jui Kuan
- Theoretical Astrophysics, Eberhard Karls University of Tübingen, Tübingen 72076, Germany
- Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Daniela D Doneva
- Theoretical Astrophysics, Eberhard Karls University of Tübingen, Tübingen 72076, Germany
| | - Stoytcho S Yazadjiev
- Theoretical Astrophysics, Eberhard Karls University of Tübingen, Tübingen 72076, Germany
- Department of Theoretical Physics, Faculty of Physics, Sofia University, Sofia 1164, Bulgaria
- Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, Acad. G. Bonchev Street 8, Sofia 1113, Bulgaria
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Motahar ZA, Blázquez-Salcedo JL, Doneva DD, Kunz J, Yazadjiev SS. Axial quasinormal modes of scalarized neutron stars with massive self-interacting scalar field. Int J Clin Exp Med 2019. [DOI: 10.1103/physrevd.99.104006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Doneva DD, Yazadjiev SS, Stergioulas N, Kokkotas KD. Differentially rotating neutron stars in scalar-tensor theories of gravity. Int J Clin Exp Med 2018. [DOI: 10.1103/physrevd.98.104039] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Yazadjiev SS, Doneva DD, Kokkotas KD. Tidal Love numbers of neutron stars in f( R) gravity. Eur Phys J C Part Fields 2018; 78:818. [PMID: 30524193 PMCID: PMC6244867 DOI: 10.1140/epjc/s10052-018-6285-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 09/24/2018] [Indexed: 06/09/2023]
Abstract
The recent detection of gravitational waves from a neutron star merger was a significant step towards constraining the nuclear matter equation of state by using the tidal Love numbers (TLNs) of the merging neutron stars. Measuring or constraining the neutron star TLNs allows us in principle to exclude or constraint many equations of state. This approach, however, has the drawback that many modified theories of gravity could produce deviations from General Relativity similar to the deviations coming from the uncertainties in the equation of state. The first and the most natural step in resolving the mentioned problem is to quantify the effects on the TLNs from the modifications of General Relativity. With this motivation in mind, in the present paper we calculate the TLNs of (non-rotating) neutron stars in R 2 -gravity. More precisely, by solving numerically the perturbation equations, we calculate explicitly the polar and the axial l = 2 TLNs for three characteristic realistic equations of state and compare the results to General Relativity. Our results show that while the polar TLNs are slightly influenced by the R 2 modification of General Relativity, the axial TLNs can be several times larger (in terms of the absolute value) compared to the general relativistic case.
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Affiliation(s)
- Stoytcho S. Yazadjiev
- Department of Theoretical Physics, Faculty of Physics, Sofia University, 1164 Sofia, Bulgaria
- Theoretical Astrophysics, Eberhard-Karls University of Tübingen, 72076 Tübingen, Germany
- Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, Acad. G. Bonchev St. 8, 1113 Sofia, Bulgaria
| | - Daniela D. Doneva
- Theoretical Astrophysics, Eberhard-Karls University of Tübingen, 72076 Tübingen, Germany
- INRNE - Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria
| | - Kostas D. Kokkotas
- Theoretical Astrophysics, Eberhard-Karls University of Tübingen, 72076 Tübingen, Germany
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Staykov KV, Popchev D, Doneva DD, Yazadjiev SS. Static and slowly rotating neutron stars in scalar-tensor theory with self-interacting massive scalar field. Eur Phys J C Part Fields 2018; 78:586. [PMID: 30100815 PMCID: PMC6061109 DOI: 10.1140/epjc/s10052-018-6064-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/12/2018] [Indexed: 06/08/2023]
Abstract
Binary pulsar observations and gravitational wave detections seriously constrained scalar-tensor theories with massless scalar field allowing only small deviations from general relativity. If we consider a nonzero mass of the scalar field, though, significant deviations from general relativity are allowed for values of the parameters that are in agreement with the observations. In the present paper we extend this idea and we study scalar-tensor theory with massive field with self-interaction term in the potential. The additional term suppresses the scalar field in the neutron star models in addition to the effect of the mass of the scalar field but still, large deviations from pure GR can be observed for values of the parameters that are in agreement with the observations.
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Affiliation(s)
- Kalin V. Staykov
- Department of Theoretical Physics, Faculty of Physics, Sofia University, 1164 Sofia, Bulgaria
| | - Dimitar Popchev
- Department of Theoretical Physics, Faculty of Physics, Sofia University, 1164 Sofia, Bulgaria
| | - Daniela D. Doneva
- Theoretical Astrophysics, Eberhard Karls University of Tübingen, 72076 Tübingen, Germany
- INRNE, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria
| | - Stoytcho S. Yazadjiev
- Department of Theoretical Physics, Faculty of Physics, Sofia University, 1164 Sofia, Bulgaria
- Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, Acad. G. Bonchev Street 8, 1113 Sofia, Bulgaria
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Doneva DD, Yazadjiev SS. New Gauss-Bonnet Black Holes with Curvature-Induced Scalarization in Extended Scalar-Tensor Theories. Phys Rev Lett 2018; 120:131103. [PMID: 29694191 DOI: 10.1103/physrevlett.120.131103] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 01/18/2018] [Indexed: 06/08/2023]
Abstract
In the present Letter, we consider a class of extended scalar-tensor-Gauss-Bonnet (ESTGB) theories for which the scalar degree of freedom is excited only in the extreme curvature regime. We show that in the mentioned class of ESTGB theories there exist new black-hole solutions that are formed by spontaneous scalarization of the Schwarzschild black holes in the extreme curvature regime. In this regime, below certain mass, the Schwarzschild solution becomes unstable and a new branch of solutions with a nontrivial scalar field bifurcates from the Schwarzschild one. As a matter of fact, more than one branch with a nontrivial scalar field can bifurcate at different masses, but only the first one is supposed to be stable. This effect is quite similar to the spontaneous scalarization of neutron stars. In contrast to the standard spontaneous scalarization of neutron stars, which is induced by the presence of matter, in our case, the scalarization is induced by the curvature of the spacetime.
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Affiliation(s)
- Daniela D Doneva
- Theoretical Astrophysics, Eberhard Karls University of Tübingen, Tübingen 72076, Germany
- INRNE-Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria
| | - Stoytcho S Yazadjiev
- Theoretical Astrophysics, Eberhard Karls University of Tübingen, Tübingen 72076, Germany
- Department of Theoretical Physics, Faculty of Physics, Sofia University, Sofia 1164, Bulgaria
- Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, Acad. G. Bonchev Street 8, Sofia 1113, Bulgaria
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Yazadjiev SS, Doneva DD, Kokkotas KD. Oscillation modes of rapidly rotating neutron stars in scalar-tensor theories of gravity. Int J Clin Exp Med 2017. [DOI: 10.1103/physrevd.96.064002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Staykov KV, Doneva DD, Yazadjiev SS, Kokkotas KD. Gravitational wave asteroseismology of neutron and strange stars inR2gravity. Int J Clin Exp Med 2015. [DOI: 10.1103/physrevd.92.043009] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Doneva DD, Yazadjiev SS, Staykov KV, Kokkotas KD. Universal I-Q relations for rapidly rotating neutron and strange stars in scalar-tensor theories. Int J Clin Exp Med 2014. [DOI: 10.1103/physrevd.90.104021] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Doneva DD, Kokkotas KD, Stefanov IZ, Yazadjiev SS. Time evolution of the radial perturbations and linear stability of solitons and black holes in a generalized Skyrme model. Int J Clin Exp Med 2011. [DOI: 10.1103/physrevd.84.084021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Stefanov IZ, Yazadjiev SS, Gyulchev GG. Connection between black-hole quasinormal modes and lensing in the strong deflection limit. Phys Rev Lett 2010; 104:251103. [PMID: 20867359 DOI: 10.1103/physrevlett.104.251103] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Indexed: 05/29/2023]
Abstract
The purpose of the current Letter is to give some relations between gravitational lensing in the strong-deflection limit and the frequencies of the quasinormal modes of spherically symmetric, asymptotically flat black holes. On the one side, the relations obtained can give a physical interpretation of the strong-deflection limit parameters. On the other side, they also give an alternative method for the measurement of the frequencies of the quasinormal modes of spherically symmetric, asymptotically flat black holes. They could be applied to the localization of the sources of gravitational waves and could tell us what frequencies of the gravitational waves we could expect from a black hole acting simultaneously as a gravitational lens and a source of gravitational waves.
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Affiliation(s)
- Ivan Zh Stefanov
- Department of Applied Physics, Technical University of Sofia 8, St. Kliment Ohridski Blvd., 1000 Sofia, Bulgaria.
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Doneva DD, Yazadjiev SS, Kokkotas KD, Stefanov IZ, Todorov MD. Charged anti–de Sitter scalar-tensor black holes and their thermodynamic phase structure. Int J Clin Exp Med 2010. [DOI: 10.1103/physrevd.81.104030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Yazadjiev SS, Nedkova PG. Magnetized configurations with black holes and Kaluza-Klein bubbles: Smarr-like relations and the first law. Int J Clin Exp Med 2009. [DOI: 10.1103/physrevd.80.024005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Yazadjiev SS. Geodesically complete nondiagonal inhomogeneous cosmological solutions in dilatonic gravity with a stiff perfect fluid. Int J Clin Exp Med 2002. [DOI: 10.1103/physrevd.66.024031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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