共查询到20条相似文献，搜索用时 671 毫秒
1.
L. C. Garcia de Andrade 《Astrophysics and Space Science》1992,198(1):79-83
The equivalence of Lagrangian containing gravitational, electromagnetic, scalar, and torsion fields is discussed. It is shown that the equation for the variation of the scalar field leads to a torsion wave equation generated by electromagnetic field leads to a torsion wave equation generated by electromagnetic fields. The system is proved to be equivalent to a Proca field coupling torsion non-minimally to a massive photon and having the scalar Higgs field as a strength of this photon-torsion coupling. The generalized Maxwell equations containing the scalar fields are obtained. The torsion potential around the Sun or a more massive collapsing star in the weak field limit is estimated. 相似文献
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Celestial coordinate reference systems in curved space-time 总被引：1，自引：1，他引：0
S. M. Kopejkin 《Celestial Mechanics and Dynamical Astronomy》1988,44(1-2):87-115
4.
Pan Rong-shi Wang Jia-ji Yan Hao-jian Tang Guo-qiang Huang Cheng 《Chinese Astronomy and Astrophysics》1984,8(4):319-324
Starting from the equation for the path of a photon in a gravitational field, we give a method of calculating the deflection of starlight in the solar field. The transformation from the non-inertial system at the Sun to the locally inertial system of the observer is considered. Calculation was made under the Schwarzschild metric. Our calculated results for the deflection before making coordinate transformation agree well with the results according to the IAU formulae, but when an accuracy of 0'.'001 is required, then the coordinate transformation must be included. 相似文献
5.
C. C. Leiby Jr. 《Astrophysics and Space Science》1986,122(1):157-161
A vector theory of electromagnetism and gravitation has indicated a possible equivalence of gravitational energy and electric charge. If true, the resulting electromagnetic and gravitational forces within a stationary, gravitationally collapsed body of radiusR=GM/c
2 are everywhere in balance within the body, if it has a radial mass density distribution proportional to 1/r
2. In addition, radial perturbation of such a body will result in a force imbalance which is restorative. Hence, the equilibrium is stable. 相似文献
6.
Vladimír Majerník 《Astrophysics and Space Science》1982,84(1):191-204
The Maxwell-like gravitational field equations have been generalized and coupled through the gravitational four-potential on the electromagnetic Maxwell's equations. It is shown that this has several astrophysical consequences, of which the main are the following (i) the gravitational instability of a system of mass bodies manifesting itself by a Hubble-like motion on cosmological scales, (ii) the possible change of light intensity propagating through a large distance (and so a possible change of the real energy output of some very distant objects, e.g., quasars), (iii) non-stability of a planetary system on the cosmological time scales, due to the momentum increase of the moving bodies in a generalized gravitational field. 相似文献
7.
Vladimír Majerník 《Astrophysics and Space Science》1982,82(2):473-476
We propose a coupling between the gravitational and electromagnetic fields so that we consider the electrodynamical Maxwell's equations as the basic ones and add the four-vector of gravitational potential to the differential operators occurring in it. It is shown that by means of this coupling all well-known tests of Einstein's theory of gravitation connected with the propagation of light in gravitational field can be correctly calculated. 相似文献
8.
R. Illge 《Astronomische Nachrichten》1988,309(4):253-257
9.
Bijan Saha 《Astrophysics and Space Science》2007,312(1-2):3-11
We consider a system of nonlinear spinor and a Bianchi type I gravitational fields in presence of viscous fluid. The nonlinear
term in the spinor field Lagrangian is chosen to be λ
F, with λ being a self-coupling constant and F being a function of the invariants I an J constructed from bilinear spinor forms S and P. Self-consistent solutions to the spinor and BI gravitational field equations are obtained in terms of τ, where τ is the volume scale of BI universe. System of equations for τ and ε, where ε is the energy of the viscous fluid, is deduced. This system is solved numerically for some special cases.
相似文献
10.
Plane-symmetric solutions of Einstein's field equations in vacuum, in the presence of electromagnetic fields and with cosmological constant are explored in null coordinates. The gravitational field of an infinite plane (uncharged and charged both) is thus obtained in a simple and systematic way. The method adopted for these solutions has possibilities of generalization. 相似文献
11.
S. Capozziello M. De Laurentis I. De Martino M. Formisano D. Vernieri 《Astrophysics and Space Science》2011,333(1):29-35
We discuss the possibility to obtain an electromagnetic emission accompanying the gravitational waves emitted in the coalescence
of a compact binary system. Motivated by the existence of black hole configurations with open magnetic field lines along the
rotation axis, we consider a magnetic dipole in the system, the evolution of which leads to (i) electromagnetic radiation,
and (ii) a contribution to the gravitational radiation, the luminosity of both being evaluated. Starting from the observations
on magnetars, we impose upper limits for both the electromagnetic emission and the contribution of the magnetic dipole to
the gravitational wave emission. Adopting this model for the evolution of neutron star binaries leading to short gamma ray
bursts, we compare the correction originated by the electromagnetic field to the gravitational waves emission, finding that
they are comparable for particular values of the magnetic field and of the orbital radius of the binary system. Finally we
calculate the electromagnetic and gravitational wave energy outputs which result comparable for some values of magnetic field
and radius. 相似文献
12.
Ara K. Avetissian Martin H. Minassian Vladimir V. Papoyan 《Astrophysics and Space Science》1980,69(1):71-77
The solution of the system of Maxwell-Einstein equations, which determines the external gravitational and electromagnetic fields of magneto-dipole configurations, has been obtained to a quadratic approximation of magnetic momentum. 相似文献
13.
R. Burghardt 《Astronomische Nachrichten》1983,304(2):77-82
Einstein's field equations can be written in a special way to give expressions free of any quantities which cannot be measured. These expressions are fully coordinate invariant but observer dependent. Generalized LORENTZ transformations according to TREDER 's theory serve as connecting links between the measured values of different observer systems. The field equations contain expressions for gravitational energy and stresses which satisfy covariant conservation laws. 相似文献
14.
J. N. Tokis 《Astrophysics and Space Science》1975,36(2):427-438
The general equations of angular momentum and kinetic energy of a rotating deformable (or not rigid) body are discussed for a fixed and a rotating coordinate system. A new system of equations is developed for a deformable body of arbitrary form using the Lagrangian (vector) cisplacement up to the first order terms. The equations are, then, illustrated for a self-gravitating ceformable body perturbed by tides. 相似文献
15.
M. Kutschera 《Monthly notices of the Royal Astronomical Society》2003,345(1):L1-L5
Einstein's general relativity predicts that pressure, in general stresses, plays a similar role to energy density, ε=ρ c 2 (with ρ being the corresponding mass density), in generating gravity. The source of gravitational field, the active gravitational mass density, sometimes referred to as Whittaker's mass density, is ρgrav =ρ+ 3 p / c 2 , where p is pressure in the case of an ideal fluid. Whittaker's mass is not conserved, hence its changes can propagate as monopole gravitational waves. Such waves can be generated only by astrophysical sources with varying gravitational mass. Here we show that relativistic fireballs, considered in modelling gamma-ray burst phenomena, are likely to radiate monopole gravitational waves from high-pressure plasma with varying Whittaker's mass. Also, ejection of a significant amount of initial mass-energy of the progenitor contributes to the monopole gravitational radiation. We identify monopole waves with h 11 + h 22 waves of Eddington's classification which propagate (in the z -direction) together with the energy carried by massless fields. We show that the monopole waves satisfy Einstein's equations, with a common stress-energy tensor for massless fields. The polarization mode of monopole waves is Φ22 , i.e. these are perpendicular waves which induce changes of the radius of a circle of test particles only (breathing mode). The astrophysical importance of monopole gravitational waves is discussed. 相似文献
16.
A special Lagrangian coordinate system is introduced, in which the magnetic flux tube is the main object of investigation. The flux tube is shown to behave as a nonlinear relativistic string in relation to tangential force. General and particular variational principles are also discussed. With the introduction of a Lagrangian coordinate system the relativistic magnetohydrodynamic equation of motion reduces to a set of nonlinear string equations. From these results it follows that a highly conductive plasma with a frozen-in magnetic field can be considered as a gas of nonlinear strings interacting through pressure forces. A method is developed which allows the multi-dimensional nonlinear problems of RMHD (relativistic MHD) with boundary layers to be reduced to a set of two-dimensional problems for flux tubes, i.e., nonlinear strings. 相似文献
17.
Gamal G. L. Nashed 《Astrophysics and Space Science》2013,348(2):591-598
A general tetrad fields, with an arbitrary function of radial coordinate, preserving spherical symmetry, is provided. Such tetrad is split into two matrices: The first matrix represents a Local Lorentz Transformation (LLT), which contains an arbitrary function. The second matrix represents a proper tetrad fields which satisfy the field equations of f(T) gravitational theory. This general tetrad is applied to the field equations of f(T). We derive a solution with one constant of integration to the resulting field equations of f(T). This solution gives a vanishing value of the scalar torsion. We calculate the energy associated with this solution to investigate what is the nature of the constant of integration. 相似文献
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19.
M. K. Mak T. Harko Department of Physics The Hong Kong University of Science Technology Clear Water Bay Hong Kong Department of Physics The University of Hong Kong Pokfulam Hong Kong 《中国天文和天体物理学报》2002,2(3):248-259
We present an exact analytical solution of the gravitational field equations describing a static spherically symmetric anisotropic quark matter distribution. The radial pressure inside the star is assumed to obey a linear equation of state, while the tangential pressure is a complicated function of the radial coordinate. In order to obtain the general solution of the field equations a particular density profile inside the star is also assumed. The anisotropic pressure distribution leads to an increase in the maximum radius and mass of the quark star, which in the present model is around three solar masses. 相似文献
20.
This paper is devoted to the study of gravitational charged perfect fluid collapse in Friedmann universe models with cosmological constant. For this purpose, we assume that the electromagnetic field is so weak that it does not introduce any distortion into the geometry of the spacetime. The results obtained from the junction conditions between the Friedmann and the Reissner–Nordström de Sitter spacetimes are used to solve the field equations. Further, the singularity structure and mass effects of the collapsing system on the time difference between the formation of apparent horizons and singularity have been studied. This analysis provides the validity of the Cosmic Censorship Hypothesis. It is found that the electromagnetic field affects the area of apparent horizons and their time of formation. 相似文献