• P C Vaidya

      Articles written in Pramana – Journal of Physics

    • A generalized kerr-schild metric

      P C Vaidya P V Bhatt

      More Details Abstract Fulltext PDF

      A metricgik=ηik+iξk+2(iPk) is investigated. WhenJ=0 this reduces to the well-known Kerr metric. Conditions on the vectorpi are obtained under which a geodetic, shear-free null congruenceξi in the Minkowskian space-time (with metricηik) will continue to remain geodetic and shear-free in the Riemannian space-time ofgik. A general solution of Einstein’s equationRik=σξiξk is obtained whenpiξi=0 andξi is twist-free.

    • The Kerr metric in cosmological background

      P C Vaidya

      More Details Abstract Fulltext PDF

      A metric satisfying Einstein’s equations is given which in the vicinity of the source reduces to the well-known Kerr metric and which at large distances reduces to the Robertson-Walker metric of a homogeneous cosmological model. The radius of the event horizon of the Kerr black hole in the cosmological background is found out.

    • Kerr metric in the deSitter background

      P C Vaidya

      More Details Abstract Fulltext PDF

      In addition to the Kerr metric with cosmological constant Λ several other metrics are presented giving a Kerr-like solution of Einstein’s equations in the background of deSitter universe. A new metric of what may be termed as rotating deSitter space-time—a space-time devoid of matter but containing null fluid with twisting null rays, has been presented. This metric reduces to the standard deSitter metric when the twist in the rays vanishes. Kerr metric in this background is the immediate generalization of Schwarzschild’s exterior metric with cosmological constant.

    • deSitter space-time and rotation

      P C Vaidya

      More Details Abstract Fulltext PDF

      A metric containing a parameterb is presented. It represents two distinct families of space-times, the Taub-nut family and the deSitter family, according asb=1 andb=4 respectively.

      The metric of the deSitter family of space-times contains a further parameterm. Whenm=0, the space-time is the usual homogeneous and isotropic deSitter space-time. But ifm≠0, the metric represents a space-time which is homogeneous but not isotropic satisfyingRikgik. In this space-time, the 4-velocity of an observer at rest will have non-zero twist. The metric withb=4,m≠0 is interpreted as a metric representing a “rotating deSitter space-time”.

    • Gravitational fields with space-times of Bianchi type IX

      P C Vaidya L K Patel

      More Details Abstract Fulltext PDF

      Spatially homogeneous space-times of Bianchi type IX are considered. A general scheme for the derivation of exact solutions of Einstein’s equations corresponding to perfect fluid plus pure radiation fields is outlined. Some simple rotating Bianchi type IX cosmological models are presented. The details of these solutions are also discussed.

    • Radiating Kerr particle in Einstein universe

      P C Vaidya L K Patel

      More Details Abstract Fulltext PDF

      A generalized Kerr-NUT type metric is considered in connection with Einstein field equations corresponding to perfect fluid plus a pure radiation field. A general scheme for obtaining the exact solutions of these field equations is developed. Two physically meaningful particular cases are investigated in detail. One gives the field of a radiating Kerr particle embedded in the Einstein universe. The other solution may probably represent a deSitter-like universe pervaded by a pure radiation field.

    • A spherically symmetric gravitational collapse-field with radiation

      P C Vaidya L K Patel

      More Details Abstract Fulltext PDF

      An interior spherically symmetric solution of Einstein’s field equations corresponding to perfect fluid plus a flowing radiation-field is presented. The physical 3-spacet=constant of our solution is spheroidal. Vaidya’s pure radiation field is taken as the exterior solution. The inward motion of the collapsing boundary surface follows from the equations of fit. An approximation procedure is used to get a generalization of the standard Oppenheimer-Snyder model of collapse with outflow of radiation. One such explicit solution has been given correct to second power of eccentricity of the spheroidal 3-space.

  • Pramana – Journal of Physics | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2017-2019 Indian Academy of Sciences, Bengaluru.