9,123 research outputs found
Energy Transport in the Vaidya System
Energy transport mechanisms can be generated by imposing relations between
null tetrad Ricci components. Several kinds of mass and density transport
generated by these relations are studied for the generalized Vaidya system.Comment: J.Math. Phys. (to appear
From Taub Numbers to the Bondi Mass
Taub numbers are studied on asymptotically flat backgrounds with Killing
symmetries. When the field equations are solved for a background spacetime and
higher order functional derivatives (higher order variational derivatives of
the Hilbert Lagrangean) are solved for perturbations from the background, such
perturbed space-times admit zeroth, first, and second order Taub numbers.
Zeroth order Taub numbers are Komar constants (upto numerical factors) or
Penrose-Goldberg constants of the background. For a Killing symmetry of the
background, first order Taub numbers give the contribution of the linearized
perturbation to the associated backgound quantity, such as the perturbing mass.
Second order Taub numbers give the contribution of second order perturbations
to the background quantity. The Bondi mass is a sum of first and second order
Taubs numbers on a Minkowski background.Comment: To appear in the proceedings of the 8th Marcel Grossmann Conferenc
A Spacetime in Toroidal Coordinates
We present an exact solution of Einstein's field equations in toroidal
coordinates. The solution has three regions: an interior with a string equation
of state; an Israel boundary layer; an exterior with constant isotropic
pressure and constant density, locally isometric to anti-de Sitter spacetime.
The exterior can be a cosmological vacuum with negative cosmological constant.
The size and mass of the toroidal loop depend on the size of the cosmological
constant.Comment: to appear in J. Math. Phy
Scale Symmetries of Spherical String Fluids
We consider homothetic maps in a family of spherical relativistic star
models. A generalization of Vaidya's radiating metric provides a fluid
atmosphere of radiation and strings. The similarity structure of the string
fluid is investigated.Comment: to appear in J. Math. Physic
Adding Twist to Anisotropic Fluids
We present a solution generating technique for anisotropic fluids which
preserves specific Killing symmetries. Anisotropic matter distributions that
can be used with the one parameter Ehlers-Geroch transform are discussed.
Example spacetimes that support the appropriate anisotropic stress-energy are
found and the transformation applied. The 3+1 black string solution is one of
the spacetimes with the appropriate matter distribution. Use of the transform
with a black string seed is discussed.Comment: to appear in J. Math. Phy
Two-Fluid Atmosphere for Relativistic Stars
We have extended the Vaidya radiating metric to include both a radiation
fluid and a string fluid. This paper expands our brief introduction to
extensions of the Schwarzschild vacuum which appeared in 1998 Phys. Rev. D Vol
57, R5945. Assuming diffusive transport for the string fluid, we find new
analytic solutions of Einstein's field equations.Comment: to appear in Classical and Quantum Gravit
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