In previous work we found that many of the spectral properties of x-ray binaries, including both galactic black hole candiates (GBHC) and neutron stars, were consistent with the existence of intrinsically magnetized central objects. Here we review and extend the observational evidence for the existence of intrinsically magnetized GBHC and show that their existence is consistent with a new class...

We consider 5D Einstein-Maxwell-dilaton (EMd) gravity in spacetimes with three commuting Killing vectors: one timelike and two spacelike Killing vectors, one of which is hypersurface-orthogonal. Assuming a special ansatz for the Maxwell field we show that the 2-dimensional reduced EMd equations are completely integrable. We also develop a solution generating method for explicit construction of ...

We present a code for solving the coupled Einstein-hydrodynamics equations to evolve relativistic, selfgravitating fluids. The Einstein field equations are solved in generalized harmonic coordinates on one grid using pseudospectral methods, while the fluids are evolved on another grid using shock-capturing finite difference or finite volume techniques. We show that the code accurately evolves e...

Contrary to popular mythology, Einstein did not invent the cosmological constant just in order construct his model universe. He discussed it earlier in “The Foundations of General Relativity”in connection with the proper structure of the source-free field equations. There he dismissed it as arbitrary and unnecessary. It was later that he found its inclusion to be essential to the construction o...

In previous work we found that many of the spectral properties of low mass x-ray binaries (LMXB), including galactic black hole candiates (GBHC) were consistent with the existence of intrinsically magnetized central objects. We review and extend these findings and show that the existence of intrisically magnetic BHC is consistent with a new class of solutions of the Einstein field equations of ...

The spectral, timing, and jet formation properties of neutron stars in low mass x-ray binary systems are influenced by the presence of central magnetic moments. Similar features shown by the galactic black hole candidates (GBHC) strongly suggest that their compact cores might be intrinsically magnetic as well. We show that the existence of intrinsically magnetic GBHC is consistent with a new cl...

Along the general framework of the gauge-invariant perturbation theory developed in the papers [K. Nakamura, Prog. Theor. Phys. 110 (2003), 723; ibid, 113 (2005), 481.], we re-derive the second-order Einstein equations on four-dimensional homogeneous isotropic background universe in gauge-invariant manner without ignoring any mode of perturbations. We consider the perturbations both in the univ...

Static, spherically symmetric solutions of the field equations for a particular dimensional continuation of general relativity with negative cosmological constant are found. In even dimensions the solution has many similarities with the Schwarzschild metric. In odd dimensions, the equations of motion are explicitly anti de-Sitter invariant, and the solution is alike in many ways to the 2+1 blac...

In this paper we investigate a class of solutions of Einstein equations for the planesymmetric perfect fluid case with shear and vanishing acceleration. If these solutions have shear, they must necessarily be non-static. We examine the integrable cases of the field equations systematically. Among the cases with shear we find three classes of solutions.

In recent, Kar.S et.al [ Phys Rev D 67,044005 (2003) ] have obtained static spherically symmetric solutions of the Einstein-Kalb-Ramond field equations. We have shown that their solutions, indeed, represent Wormholes. In Einstein-Cartan theory, the symmetric Christoffel connection is modified with the introduction of an anti-symmetric tensorial term,known as space time torsion, which is presume...