We prove the theorem: The necessary and sufficient condition for a spherically symmetric spacetime to represent an isothermal perfect fluid (barotropic equation of state with density falling off as inverse square of the curvature radius) distribution without boundary is that it is conformal to the “minimally” curved (gravitation only manifesting in tidal acceleration and being absent in particl...

It is shown that for cylindrically symmetric Jordan-Ehlers spacetime, either the charged scalar meson field associated with meson rest mass M or the charged perfect fluid cannot be the source for generating gravitation.

Abstract. The Tolman–Oppenheimer–Volkov [TOV] equation constrains the internal structure of general relativistic static perfect fluid spheres. We develop several “solution generating” theorems for the TOV, whereby any given solution can be “deformed” to a new solution. Because the theorems we develop work directly in terms of the physical observables — pressure profile and density profile — it ...

We give an example of a spacetime having an infinite thin rotating cylindrical shell constituted by a charged perfect fluid as a source. Then we disscuss the energy conditions and we show that our spacetime contains closed timelike curves. Trajectories of charged test particles both inside and outside the cylinder are also examined. Expression for the angular velocity of a circular motion insid...

The object of the present paper is to characterize pseudo Ricci symmetric twisted spacetimes. At first it shown that a spacetime GRW spacetime. Next, we obtain necessary and sufficient condition for be perfect fluid It also proved fluid, provided conformal curvature tensor divergence free. Moreover, investigate shear vorticity vector fields such type spacetimes pointed out its implications towa...

We show that the standard perfect fluid paradigm is not necessarily a valid description of a curved space steady state gravitational source. Simply by virtue of not being flat, curved space geometries have to possess intrinsic length scales, and such length scales can affect the fluid structure. For modes of wavelength of order or greater than such scales eikonalized geometrical optics cannot a...

In this paper, we evaluate kinematic self-similar perfect fluid and dust solutions for the most general cylindrically symmetric spacetime. We explore kinematic self-similar solutions of the first, second, zeroth and infinite kinds for parallel and orthogonal cases. It is found that the parallel case gives solutions for both perfect fluid and dust cases in all kinds except the zeroth kind of the...

The properties of a transformation previously considered for generating new perfect-fluid solutions from known ones are further investigated. It is assumed that the four-velocity of the fluid is parallel to the stationary Killing field, and also that the norm and the twist potential of the stationary Killing field are functionally related. This case is complementary to the case studied in our p...