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Basilis C. Xanthopoulos

Bio: Basilis C. Xanthopoulos is an academic researcher from University of Crete. The author has contributed to research in topics: Einstein field equations & General relativity. The author has an hindex of 19, co-authored 56 publications receiving 1047 citations. Previous affiliations of Basilis C. Xanthopoulos include Aristotle University of Thessaloniki & Max Planck Society.


Papers
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TL;DR: In this paper, a series of transformations is presented for generating stationary axially symmetric asymptotically flat vacuum solutions of Einstein's equations, which can be used to generate all stationary metrics with axial symmetry.
Abstract: A new series of transformations is presented for generating stationary axially symmetric asymptotically flat vacuum solutions of Einstein’s equations. The application requires only algebraic manipulations to be performed. Several examples are given of new stationary axisymmetric solutions obtained in this way. It is conjectured that the transformations, applied to the genral Weyl metric, can be used to generate systematically all stationary metrics with axial symmetry.

129 citations

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TL;DR: The exact static spherically symmetric solution of the coupled Einstein--massless-scalar-field equations for arbitrary spacetime dimensions is obtained.
Abstract: We obtain the exact static spherically symmetric solution of the coupled Einstein--massless-scalar-field equations for arbitrary spacetime dimensions. The general solution involves two parameters: it is asymptotically flat and the scalar field tends to zero at spacelike infinity. It exhibits a naked singularity unless the scalar field vanishes when it naturally reduces to the Schwarzschild solution in D spacetime dimensions.

94 citations

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TL;DR: In this article, it was proved that if (M,gab) is an exact vacuum solution of the equation on the background (Gab+lalb), then gab+gab is a null vector field.
Abstract: It is proved that if (M,gab) is an exact vacuum solution of Einstein’s equation, la a null vector field and if lalb satisfies the linearized equation on background (M,gab), then gab+lalb is an exact vacuum solution. Applications to the search for asymptotically flat spacetimes are discussed.

65 citations

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TL;DR: In this article, an exact solution for colliding plane impulsive gravitational waves accompanied by shock waves was obtained, which, in contrast to other known solutions, results in the development of a null surface which acts like an event horizon.
Abstract: An exact solution is obtained for colliding plane impulsive gravitational waves accompanied by shock waves, which, in contrast to other known solutions, results in the development of a null surface which acts like an event horizon. The analytic extension of the solution across the null surface reveals the existence of time-like curvature singularities along two hyperbolic arcs in the extended domain, reminiscent of the ring singularity of the Kerr metric. Besides, the space-time, in the region of the interaction of the colliding waves, is of Petrov-type D and locally isometric to the Kerr space-time in a region interior to the ergosphere. Various other aspects of the solution are also discussed.

61 citations

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TL;DR: In this paper, the Bekenstein black hole for gravity coupled to a conformal scalar field was found to exist in four space-time dimensions and was used to generate spherically symmetric, asymptotically flat solutions.
Abstract: For space‐times of arbitrary dimensionality two transformations are obtained that applied to any solution of the Einstein equations coupled to a minimally coupled scalar field construct a solution of the Einstein equations coupled to a conformal scalar field. The transformations are conformal for the metrics and algebraic for the reparametrization of the scalar fields. With these generating techniques static, spherically symmetric, asymptotically flat solutions of the Einstein‐conformal scalar field equations in arbitrary space‐time dimensions are obtained. Black hole solutions are systematically searched for and it is found that the only (nonvacuum) one exists in four space‐time dimensions. This is the Bekenstein black hole for gravity coupled to a conformal scalar field.

50 citations


Cited by
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TL;DR: The successes, as well as the limits, of perturbation theory are presented, and its role in the emerging era of numerical relativity and supercomputers is discussed.
Abstract: Perturbations of stars and black holes have been one of the main topics of relativistic astrophysics for the last few decades. They are of particular importance today, because of their relevance to gravitational wave astronomy. In this review we present the theory of quasi-normal modes of compact objects from both the mathematical and astrophysical points of view. The discussion includes perturbations of black holes (Schwarzschild, Reissner-Nordstrom, Kerr and Kerr-Newman) and relativistic stars (non-rotating and slowly-rotating). The properties of the various families of quasi-normal modes are described, and numerical techniques for calculating quasi-normal modes reviewed. The successes, as well as the limits, of perturbation theory are presented, and its role in the emerging era of numerical relativity and supercomputers is discussed.

1,569 citations

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TL;DR: In this article, the authors present explicit models for a symmetry breakdown in the cases of the Weyl (or homothetic) group, the SL(4, R), or the GL(4-R) covering subgroup.

1,474 citations

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TL;DR: This work discusses black-hole solutions of maximal supergravity theories, including black holes in anti-de Sitter space, and reviews Myers-Perry solutions, black rings, and solution-generating techniques.
Abstract: We review black-hole solutions of higher-dimensional vacuum gravity and higher-dimensional supergravity theories. The discussion of vacuum gravity is pedagogical, with detailed reviews of Myers-Perry solutions, black rings, and solution-generating techniques. We discuss black-hole solutions of maximal supergravity theories, including black holes in anti-de Sitter space. General results and open problems are discussed throughout.

860 citations