Article
Astronomy & Astrophysics
H. Garcia-Compean, V. S. Manko, C. J. Ramirez-Valdez
Summary: This paper extends our previous research results to the case of axially symmetric dyonic black holes and introduces the classical Ernst formalism with the magnetic potential 0m. We analyze in detail the case of the dyonic Kerr-Newman black hole and correctly evaluate the Komar mass, proving the validity of the standard Tomimatsu mass formula.
Article
Physics, Multidisciplinary
Alexandre Le Tiec, Marc Casals
Summary: The study reveals that under certain conditions, black holes can be tidally deformed by external gravitational fields, leading to the existence of Love tensors. However, these Love tensors vanish for non-rotating black holes or axisymmetric tidal perturbations, but are non-zero for spinning black holes.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Particles & Fields
Markus B. Froeb
Summary: Research shows that the Kerr-Schild ansatz can be extended into different gravity theories, with solutions depending differently on the choice of tetrad in the framework.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Samuel D. Upton, Adam Pound
Summary: Research shows that highly regular gauges can more efficiently extract system parameters from EMRI waveforms in numerical calculations. By deriving expressions for the metric perturbation and the distributional source of the second-order field, it is possible to calculate the second-order self-force more accurately.
Article
Astronomy & Astrophysics
Alexander Kamenshchik, Polina Petriakova
Summary: We investigate the application of the Newman-Janis algorithm to a specific regular static solution supported by a scalar field with a nonstandard kinetic term. While coordinate complexification leads to the appearance of a regular Kerr-like black hole, we encounter discrepancies in Einstein's equations within a narrow domain, primarily due to the regularization parameter. Beyond this intriguing region, the geometry corresponds to the familiar Kerr spacetime.
Article
Physics, Particles & Fields
Shokoufe Faraji, Audrey Trova, Hernando Quevedo
Summary: The main goal of this paper is to investigate the physical properties of equilibrium sequences of non-self gravitating surfaces characterizing Thick disks around a rotating deformed compact object, and to evaluate the rotation and quadrupole parameters of the central compact object.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Vitor Cardoso, Arianna Foschi
Summary: Tidal perturbations play a crucial role in studying dynamics in the classical two-body system, with the effects of a companion on timelike and null geodesics of a Schwarzschild black hole being investigated. New effects are discovered, including closed lightlike trajectories which are elliptic for equatorial companions. The results show that the light ring period can vary in length depending on the location of the companion.
Article
Astronomy & Astrophysics
Rajes Ghosh, Selim Sk, Sudipta Sarkar
Summary: Several black hole solutions violate the original version of the no-hair conjecture, leading to the development of a new theorem that establishes a universal lower bound on the extension of hairs outside any four-dimensional black hole solutions. This work presents a novel generalization of this theorem, applicable to arbitrary spacetime dimensions, without using gravitational field equations. The hairosphere is found to extend to the innermost light ring of the black hole spacetime, regardless of the underlying theory of gravity. Possible observational implications and other consequences are discussed.
Article
Astronomy & Astrophysics
Nicholas Loutrel, Richard Brito, Andrea Maselli, Paolo Pani
Summary: The study investigates the dynamics of binary systems and gravitational wave corrections due to mass quadrupole effects. The results suggest that phase constraints can be achieved with gravitational wave detectors under certain conditions.
Article
Astronomy & Astrophysics
Alexandre Le Tiec, Marc Casals, Edgardo Franzin
Summary: This study explores the linear response of a Kerr black hole to multipolar tidal fields, revealing that the response does not vanish under nonaxisymmetric perturbations of spinning black holes, and introducing the concepts of tidal Love numbers and tidal Love tensor.
Article
Astronomy & Astrophysics
Goncalo Castro, Leonardo Gualtieri, Paolo Pani
Summary: Numerical evidence suggests a surprising hidden symmetry among the rotational tidal Love numbers with opposite parities, which are associated with perturbations belonging to separate sectors. This symmetry, proposed based on a Lagrangian description of the tidal interaction in a binary system, holds independently of the equation of state of the star.
Article
Astronomy & Astrophysics
Ulf Danielsson, Suvendu Giri
Summary: In this paper, a string theory inspired alternative to gravitational collapse is proposed, and the rotating black shells are examined for stability, with flux parameters determined by constraints from dynamical analysis. The preferred quadrupole moment is found to be 7% less than Kerr, based on physical assumptions.
Article
Astronomy & Astrophysics
Tieguang Zi, Jian-dong Zhang, Hui-Min Fan, Xue-Ting Zhang, Yi-Ming Hu, Changfu Shi, Jianwei Mei
Summary: Studying the characteristics of massive black holes through extreme mass ratio inspiral (EMRI) events and testing the no-hair theorem is crucial, and the TianQin space-based gravitational wave observatory can accurately measure the quadrupole moment parameter. The choice of waveform cutoff has a significant impact on the results.
Article
Astronomy & Astrophysics
Nicholas Loutrel, Paolo Pani, Nicolas Yunes
Summary: In general relativity, the no-hair theorems determine the multipolar structure of isolated black holes, but in modified gravity or when dealing with non-black hole compact objects, the multipolar structure of the exterior spacetime may differ. The multipolar structure plays a crucial role in the dynamics and gravitational wave emissions of binary black holes, and characterizing these effects can provide valuable insights into fundamental physics. This study proposes an extension of the parametrized post-Einsteinian framework to incorporate precession effects, which can serve as a basis for future tests of general relativity using gravitational waves from precessing binaries.
Article
Astronomy & Astrophysics
V. S. Manko, E. Ruiz
Summary: In this paper, two physically meaningful configurations of a pair of equal Kerr-Newman corotating black holes separated by a massless strut are elaborated using the general equatorially symmetric two-soliton solution. The thermodynamic properties of these binary configurations are studied and the first law of thermodynamics taking correctly into account the magnetic field contribution is formulated for each case.
Article
Astronomy & Astrophysics
J. L. Hernandez-Pastora
CLASSICAL AND QUANTUM GRAVITY
(2019)
Article
Astronomy & Astrophysics
Luis Herrera
Article
Physics, Multidisciplinary
Luis Herrera
Article
Physics, Multidisciplinary
Luis Herrera
Article
Physics, Particles & Fields
J. L. Hernandez-Pastora
EUROPEAN PHYSICAL JOURNAL C
(2020)
Article
Astronomy & Astrophysics
Luis Herrera
Summary: This passage discusses how the vorticity of world-lines of observers associated with the rotation of a massive body was reported by Lense and Thirring more than a century ago. The analysis in this paper provides a comprehensive physical picture of frame-dragging, identifying the physical quantities responsible for the vorticity in different scenarios. The observational consequences of the results are also discussed.
Editorial Material
Physics, Multidisciplinary
Luis Herrera
Article
Physics, Multidisciplinary
Luis Herrera, Alicia Di Prisco, Justo Ospino
Summary: This study examines fluid distributions with hyperbolic symmetry, which resemble Lemaitre-Tolman-Bondi (LTB) solutions in many aspects. It explores both pure dust models and dissipative models with anisotropic pressure, finding that models with a vanishing complexity factor are necessarily nondissipative and satisfy the stiff equation of state.
Article
Physics, Particles & Fields
J. L. Hernandez-Pastora
Summary: In this study, using an integral definition and the generalized relativistic Gauss theorem, the specific link between relativistic multipole moments and the source of the exterior space-time is proven, and the relativistic quadrupole moment for the Erez-Rosen space-time is obtained.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Multidisciplinary Sciences
Luis Herrera, Alicia Di Prisco, Justo Ospino
Summary: This article searches for exact analytical solutions to spherically symmetric dissipative fluid distributions that satisfy the vanishing expansion condition (vanishing expansion scalar Theta). To achieve this, additional restrictions are imposed to allow integration of the field equations. The solutions are analyzed, and possible applications to astrophysical scenarios as well as alternative approaches to obtaining new solutions are discussed.
Article
Multidisciplinary Sciences
Luis Herrera, Alicia Di Prisco, Justo Ospino
Summary: The study focuses on dissipative fluid distributions with hyperbolical symmetry, revealing the negative energy density and the inaccessibility of the central region. The inner region is described by a vacuum cavity around the center, and interesting thermodynamical properties are found through a causal transport equation. Several exact analytical solutions, evolving in a quasi-homologous regime and satisfying the vanishing complexity factor condition, are presented.
Article
Astronomy & Astrophysics
L. Herrera, A. Di Prisco, J. Carot
Article
Astronomy & Astrophysics
L. Herrera, A. Di Prisco, J. Ospino
Article
Astronomy & Astrophysics
L. Herrera, A. Di Prisco, J. Ospino
Article
Astronomy & Astrophysics
L. Herrera, A. Di Prisco, J. Carot