scholarly journals Spherically symmetric black holes and affine-null metric formulation of Einstein’s equations

2021 ◽  
Vol 104 (8) ◽  
Author(s):  
Emanuel Gallo ◽  
Carlos Kozameh ◽  
Thomas Mädler ◽  
Osvaldo M. Moreschi ◽  
Alejandro Perez
Keyword(s):  
Black Holes ◽  
Spherically Symmetric ◽  
Einstein’S Equations ◽  
Einstein's Equations

scholarly journals Black Holes or an Objects without Event Horizon?

2021 ◽  
Author(s):  
Leonid Verozub
Keyword(s):  
Black Holes ◽  
Event Horizon ◽  
Fermi Gas ◽  
Einstein’S Equations ◽  
Einstein's Equations ◽  
Degenerate Fermi Gas

The paper substantiates the possibility that objects that we usually identify with black holes are self-gravitating, fully or partially degenerate Fermi gas. This follows from the modification of Einstein's equations, which is based on a mathematical fact that the author of the GR could not have known in his time.

Numerical relativity: challenges for computational science

Acta Numerica ◽  
1999 ◽  
Vol 8 ◽  
pp. 1-45 ◽  
Author(s):  
Gregory B. Cook ◽  
Saul A. Teukolsky
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Numerical Relativity ◽  
Hyperbolic Systems ◽  
Nonlinear Partial Differential Equations ◽  
Elliptic Systems ◽  
Computational Domain ◽  
Einstein’S Equations ◽  
Einstein's Equations ◽  
3 Dimensional

We describe the burgeoning field of numerical relativity, which aims to solve Einstein's equations of general relativity numerically. The field presents many questions that may interest numerical analysts, especially problems related to nonlinear partial differential equations: elliptic systems, hyperbolic systems, and mixed systems. There are many novel features, such as dealing with boundaries when black holes are excised from the computational domain, or how even to pose the problem computationally when the coordinates must be determined during the evolution from initial data. The most important unsolved problem is that there is no known general 3-dimensional algorithm that can evolve Einstein's equations with black holes that is stable. This review is meant to be an introduction that will enable numerical analysts and other computational scientists to enter the field. No previous knowledge of special or general relativity is assumed.

scholarly journals Effective gravitational mass of the Ayón-Beato and García metric

2015 ◽  
Vol 30 (25) ◽  
pp. 1550120 ◽  
Author(s):  
A. K. Sinha ◽  
G. K. Pandey ◽  
A. K. Bhaskar ◽  
B. C. Rai ◽  
A. K. Jha ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Electric Charge ◽  
Radial Distance ◽  
Gravitational Mass ◽  
Spherically Symmetric ◽  
Einstein’S Equations ◽  
Einstein's Equations ◽  
Adm Mass

In this paper, we calculate the effective gravitational mass of Ayón-Beato and García (AG) regular (nonsingular) static spherically symmetric asymptotically Minkowskian metric that is a solution to Einstein’s equations coupled with a nonlinear electromagnetic field. The effective gravitational mass is negative, zero, or positive that depends on the ratio of magnitude of electric charge to the ADM mass and the ratio of the radial distance to the ADM mass. As expected, at large values of radial distance, our result gives effective gravitational mass of the Reissner–Nordström metric.

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