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Title: Are black holes in alternative theories serious astrophysical candidates? The case for Einstein-dilaton-Gauss-Bonnet black holes

Abstract

It is generally accepted that Einstein's theory will get some as yet unknown corrections, possibly large in the strong-field regime. An ideal place to look for these modifications is in the vicinities of compact objects such as black holes. Here, we study dilatonic black holes, which arise in the framework of Gauss-Bonnet couplings and one-loop corrected four-dimensional effective theory of heterotic superstrings at low energies. These are interesting objects as a prototype for alternative, yet well-behaved gravity theories: they evade the 'no-hair' theorem of general relativity but were proven to be stable against radial perturbations. We investigate the viability of these black holes as astrophysical objects and try to provide some means to distinguish them from black holes in general relativity. We start by extending previous works and establishing the stability of these black holes against axial perturbations. We then look for solutions of the field equations describing slowly rotating black holes and study geodesic motion around this geometry. Depending on the values of mass, dilaton charge, and angular momentum of the solution, one can have differences in the innermost-stable-circular-orbit location and orbital frequency, relative to black holes in general relativity. In the most favorable cases, the difference amounts tomore » a few percent. Given the current state-of-the-art, we discuss the difficulty of distinguishing the correct theory of gravity from electromagnetic observations or even with gravitational-wave detectors.« less

Authors:
;  [1];  [2]
  1. Dipartimento di Fisica, Universita di Cagliari, and INFN sezione di Cagliari, Cittadella Universitaria 09042 Monserrato (Italy)
  2. (United States)
Publication Date:
OSTI Identifier:
21308326
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 79; Journal Issue: 8; Other Information: DOI: 10.1103/PhysRevD.79.084031; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0556-2821
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANGULAR MOMENTUM; ASTROPHYSICS; BLACK HOLES; COUPLING; DISTURBANCES; EINSTEIN FIELD EQUATIONS; FOUR-DIMENSIONAL CALCULATIONS; GENERAL RELATIVITY THEORY; GRAVITATION; GRAVITATIONAL WAVE DETECTORS; MASS; MATHEMATICAL SOLUTIONS; MODIFICATIONS; ORBITS; PERTURBATION THEORY; STABILITY; SUPERSTRING MODELS

Citation Formats

Pani, Paolo, Cardoso, Vitor, and Centro Multidisciplinar de Astrofisica-CENTRA, Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisboa, Portugal, and Department of Physics and Astronomy, University of Mississippi, University, Mississippi 38677-1848. Are black holes in alternative theories serious astrophysical candidates? The case for Einstein-dilaton-Gauss-Bonnet black holes. United States: N. p., 2009. Web. doi:10.1103/PHYSREVD.79.084031.
Pani, Paolo, Cardoso, Vitor, & Centro Multidisciplinar de Astrofisica-CENTRA, Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisboa, Portugal, and Department of Physics and Astronomy, University of Mississippi, University, Mississippi 38677-1848. Are black holes in alternative theories serious astrophysical candidates? The case for Einstein-dilaton-Gauss-Bonnet black holes. United States. doi:10.1103/PHYSREVD.79.084031.
Pani, Paolo, Cardoso, Vitor, and Centro Multidisciplinar de Astrofisica-CENTRA, Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisboa, Portugal, and Department of Physics and Astronomy, University of Mississippi, University, Mississippi 38677-1848. Wed . "Are black holes in alternative theories serious astrophysical candidates? The case for Einstein-dilaton-Gauss-Bonnet black holes". United States. doi:10.1103/PHYSREVD.79.084031.
@article{osti_21308326,
title = {Are black holes in alternative theories serious astrophysical candidates? The case for Einstein-dilaton-Gauss-Bonnet black holes},
author = {Pani, Paolo and Cardoso, Vitor and Centro Multidisciplinar de Astrofisica-CENTRA, Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisboa, Portugal, and Department of Physics and Astronomy, University of Mississippi, University, Mississippi 38677-1848},
abstractNote = {It is generally accepted that Einstein's theory will get some as yet unknown corrections, possibly large in the strong-field regime. An ideal place to look for these modifications is in the vicinities of compact objects such as black holes. Here, we study dilatonic black holes, which arise in the framework of Gauss-Bonnet couplings and one-loop corrected four-dimensional effective theory of heterotic superstrings at low energies. These are interesting objects as a prototype for alternative, yet well-behaved gravity theories: they evade the 'no-hair' theorem of general relativity but were proven to be stable against radial perturbations. We investigate the viability of these black holes as astrophysical objects and try to provide some means to distinguish them from black holes in general relativity. We start by extending previous works and establishing the stability of these black holes against axial perturbations. We then look for solutions of the field equations describing slowly rotating black holes and study geodesic motion around this geometry. Depending on the values of mass, dilaton charge, and angular momentum of the solution, one can have differences in the innermost-stable-circular-orbit location and orbital frequency, relative to black holes in general relativity. In the most favorable cases, the difference amounts to a few percent. Given the current state-of-the-art, we discuss the difficulty of distinguishing the correct theory of gravity from electromagnetic observations or even with gravitational-wave detectors.},
doi = {10.1103/PHYSREVD.79.084031},
journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 8,
volume = 79,
place = {United States},
year = {2009},
month = {4}
}